everybody,
i'm working with a high speed RS422 pci board (OXPCIe958) under Ubuntu.
The device can work up to 15Mbps. I need to work at 10Mbps, but i notice that under Linux,
if we use termois, the maximum speed that can be specified is B4000000 (4 Mbps).
Is there any way to specify custom baund rate in linux?? I tried to change the values
in termois.h:
#define B1152000 0010011
#define B1500000 0010012
#define B2000000 0010013
#define B2500000 0010014
#define B3000000 0010015
#define B3500000 0010016
#define B4000000 0010017 --> by default this is the last value
#define B4500000 0010018 --> Added
#define B5000000 0010020 --> Added
//#define __MAX_BAUD B4000000 --> Default value
#define __MAX_BAUD B10000000
But changes doesn't work. I cannot understand the meaning of the value assigned to BXXXXXX!!
The device works natively on linux and no driver must be specified. Looking into the device's datasheet, i saw that to specify the target baund rate, we must set some registers that change the prescaler, the latch divisor and the sample clock.
According to the data sheet, tha baund rate is given by:
Baundrate = inputclok/(sampleClock*divisor*prescaler)
Is there a way to set this registers under linux? the driver are in 8250.c and 8250_pci.c
Thanks in advance
This page has a Linux kernel patch that adds direct exposure of the registers, so that ioctl() can be used to program custom baud rates. It's pretty old though, but might be useful for you.
Related
Using Nucleo STM32H723 board making an alive LED toggle in the StartDefaultTask.
osDelay(10000) gives exactly30 seconds of delay. I'm using timer7 as systick timer.
Bonus info:
FreeRTOSConfig.h
#define configCPU_CLOCK_HZ ( SystemCoreClock )
"SystemCoreClock" is initially set to 64MHz (HSI) but during start-up initialized to 216MHz (SYSClk). If I edit "FreeRTOSConfig.h" and set "configCPU_CLOCK_HZ" to 64000000 osDelay is now correct, but I would like to be able to generate the clock and rtos config with CubeIDE.
Maybe someone can tell me what I am doing wrong...
I am not familiar with that board, but I think the OS thinks SysTick ticks # 1/3 speed of its actual (hardware) speed. You have to sync that value to the OS. Check your FreeRTOSConfig.h file for configSYSTICK_CLOCK_HZ and related parameters. As for the CubeIDE/FreeRTOS integration, check the suitable extensions/expansions of the IDE. Other than that, you have to edit files manually...
I have a Cincoze DE-1000 industrial PC, that features a Fintek F81866A chipset. I have to manage the DIO pins to read the input from a phisical button and to set on/off a LED. I have experience in C++ programming, but not at low/hardware level.
On the documentation accompanying the PC, there is the following C code:
#define AddrPort 0x4E
#define DataPort 0x4F
//<Enter the Extended Function Mode>
WriteByte(AddrPort, 0x87)
WriteByte(AddrPort, 0x87) //Must write twice to entering Extended mode
//<Select Logic Device>
WriteByte(AddrPort, 0x07)
WriteByte(DataPort, 0x06)
//Select logic device 06h
//<Input Mode Selection> //Set GP74 to GP77 input mode
WriteByte(AddrPort, 0x80) //Select configuration register 80h
WriteByte(DataPort, 0x0X)
//Set (bit 4~7) = 0 to select GP 74~77 as Input mode.
//<input Value>
WriteByte(AddrPort, 0x82) // Select configuration register 82h
ReadByte(DataPort, Value) // Read bit 4~7(0xFx)= GP74 ~77 as High.
//<Leave the Extended Function Mode>
WriteByte(AddrPort, 0xAA)
As far as I understood, the above code should read the value of the four input PINs (so it should read 1 for each PIN), but I am really struggling to understand how it actually works. I have understood the logic (selecting an address and reading/writing an hex value to it), but I cannot figure out what kind of C instructions WriteByte() and ReadByte() are. Also, I do not understand where Value in the line ReadByte(DataPort, Value) comes from. It should read the 4 PINs all together, so it should be some kind of "byte" type and it should contain 1 in its bits 4-7, but again I cannot really grasp the meaning of that line.
I have found an answer for a similar chip, but it did not help me in understanding.
Please advice me or point me to some relevant documentation.
That chip looks like a fairly typical Super I/O controller, which is basically the hub where all of the "slow" peripherals are combined into a single chipset.
Coreboot has a wiki page that talks about how to access the super I/O.
On the PC architecture, Port I/O is accomplished using special CPU instructions, namely in and out. These are privileged instructions, which can only be used from a kernel-mode driver (Ring 0), or a userspace process which has been given I/O privileges.
Luckily, this is easy in Linux. Check out the man page for outb and friends.
You use ioperm(2) or alternatively iopl(2) to tell the kernel to allow the user space application to access the I/O ports in question. Failure to do this will cause the application to receive a segmentation fault.
So we could adapt your function into a Linux environment like this:
/* Untested: Use at your own risk! */
#include <sys/io.h>
#include <stdio.h>
#define ReadByte(port) inb(port)
#define WriteByte(port, val) outb(val, port)
int main(void)
{
if (iopl(3) < 0) {
fprintf(stderr, "Failed to get I/O privileges (are you root?)\n");
return 2;
}
/* Your code using ReadByte / WriteByte here */
}
Warning
You should be very careful when using this method to talk directly to the Super IO, because your operating system almost certainly has device drivers that are also talking to the chip.
The right way to accomplish this is to write a device driver that properly coordinates with other kernel code to avoid concurrent access to the device.
The Linux kernel provides GPIO access to at least some Super I/O devices; it should be straightforward to port one of these to your platform. See this pull request for the IT87xx chipset.
WriteByte() and ReadByte() are not part of the C language. By the looks of things, they are functions intended to be placeholders for some form of system call for the OS kernel port IO (not macros doing memory mapped IO directly as per a previous version of this answer).
The prototypes for the functions would be something along the lines of:
#include <stdint.h>
void WriteByte(unsigned port, uint8_t value);
void ReadByte(unsigned port, uint8_t *value);
Thus the Value variable would be a pointer to an 8 bit unsigned integer (unsigned char could also be used), something like:
uint8_t realValue;
uint8_t *Value = &realValue;
Of course it would make much more sense to have Value just be a uint8_t and have ReadByte(DataPort, &Value). But then the example code also doesn't have any semicolons, so was probably never anything that actually ran. Either way, this is how Value would contain the data you are looking for.
I also found some more documentation of the registers here - https://www.electronicsdatasheets.com/download/534cf560e34e2406135f469d.pdf?format=pdf
Hope this helps.
I have an STM32L051 and want to drive an external DAC (SPI).
For that I would like to use the feature, mentioned in the manual, to output the internal reference voltage to the PB1 pin of the STM32.
I use the STM32Cube HAL as a basis. However the examples of using the VREF are limited to internal use for ADCs and comparators.
If I understand correctly, I can use the CFGR3 register to both enable the VREF as well as connect it to the PB1. Using the Cube drivers, I can use the HAL_SYSCFG_VREFINT_OutputSelect(SYSCFG_VREFINT_OUT_PB1) function, but to enable it, I should use either HAL_ADCEx_EnableVREFINT() or HAL_COMPEx_EnableVREFINT(). The manual information on SEL_VREF_OUT indicates that ENBUF_VREFINT_ADC must be set.
Furthermore no mention is made about the configuration of the pin itself. Should I simply declare it as a DAC Pin? An ADC Pin?
Answer
It is as simple as
if ( HALD_ADCEx_EnableVREFINT() != HAL_OK )
{
Error_Handling();
}
HAL_SYSCFG_VREFINT_OutputSelect(SYSCFG_VREFINT_OUT_PB1);
And I can see the 1.22 V on the PB1 output.
It does not require further pin (GPIO) configuration.
Complications and justification for the question (can be skipped)
I had some issues with the board from out electronic dept. and thus switched to the STM32L053-Discovery board. The above solution did not work, and I kept seeing 0V on PB1 (or PB0).
I assumed that was due to some configuration missing. However, after some further tests, I actually found that on that Discovery board, both PB1 and PB0 are reserved for a sensor. By closing the SB23 bridge, I could use PB1 back to the GPIO, and thus see the reference voltage on the pin.
I want to make PiFm https://github.com/rm-hull/pifm/blob/master/pifm.cpp compatible on OrangePi One ( h3 AllWinner ARM processor )
I guess, to do compatible i just? set the good register addresses no ?
On PiFm i found those address :
#define CM_GP0CTL (0x7e101070)
#define GPFSEL0 (0x7E200000)
#define CM_GP0DIV (0x7e101074)
#define CLKBASE (0x7E101000)
#define DMABASE (0x7E007000)
#define PWMBASE (0x7e20C000) /* PWM controller */
But on the H3 datasheet http://dl.linux-sunxi.org/H3/Allwinner_H3_Datasheet_V1.0.pdf i can't translate these addresses.
I'm not a expert on ARM/Programmation but PiFm will work on OrangePi One ?
(Sorry for my english, i'm french)
Thanks by advance
Regards
Converting this program to run on the Allwinner SoC would involve rewriting it entirely, if it's even possible.
PiFm depends on being able to turn the Broadcom SoC's PWM peripheral on and off through crafted DMA requests. This is not an option on the Allwinner; the PWM peripheral does not have a DMA port (datasheet page 193).
I have microprocessor at32uc3b0256 and I want turn on leds, (simple program from examples). To do this I use Atmel Studio. I found sample code:
#ifndef F_CPU
#define F_CPU 16000000UL // 16 MHz clock speed
#endif
#include <avr/io.h>
#include <util/delay.h>
int main(void)
{
DDRC = 0xFF; //Makes PORTC as Output
while(1) //infinite loop
{
PORTC = 0xFF; //Turns ON All LEDs
_delay_ms(1000); //1 second delay
PORTC= 0x00; //Turns OFF All LEDs
_delay_ms(1000); //1 second delay
}
}
But when i wrote it to Atmel Studio i got some errors, Atmel Studio dont see DDRC and PORTs as variable. How can I fix it?
Screen form Atmel Studio
You are using GPIO example for AVR8 architecture. AVR32 architecture is completely different introducing GPIO module as separate HW block connected through PBA (I think). There are no registers like DDRC,...
You can look at AVR32 architecture as on network of subcomponents where MCU core is only one of the modules. There are 2 main buses PBA and PBB each connected to different modules.
To make AVR32 firmware work you need do this:
configure and start main MCU core clock you want to use
AVR32 MCU core is usually running at low 32KHz clock after reset. To achieve better performance you need higher clock up to 66MHz. I usually start PLL at some common frequency and divide all clocks (CPU,PBA,PBB,HSB) from it later. As a source for the PLL you need some clock for example internal RC or oscillator driven by external crystal. If you want also USB then you need to take in mind it needs specific frequency so compromise ... For more info check SCIF module in datasheet and or in examples.
switch to it when started properly
Either wait a bit (100ms) or check if clock is running directly (SCIF module has some capabilities for it I think).
configure/start used HW modules
now do your stuff
Bootlaoder
Another thing you need to take care of is the boot loader. I do not like JTAG as I have a bad experience with it (does not take much to fry it and the programing with it is really uncomfortable). With JTAG you can easily wipe out bootloader (each chip is shipped with it) and trust me getting it back to work is really nasty.
Bootloader on the other hand is simple and elegant. For example I use FLIP and has simple comandline file for programing chip. Then I just open command prompt execute it. And on each rebuild/programming I just hit up arrow to repeat last command in the prompt and hit enter. In comparison to many clicks with JTAG is this much faster and simpler. Here example of the cmd:
avr32-objcopy -O ihex AT32UC3L064.elf AT32UC3L064.hex
Batchisp -device AT32UC3L064 -hardware RS232 -port COM1 -baudrate 115200 -operation onfail abort memory flash erase f blankcheck loadbuffer AT32UC3L064.hex program start reset 0
The avr32-objcopy.exe is in the AVR studio bin directory.
With Bootloader you need to tell the compiler your program is not starting at 0x0000 because that would be overlapping with bootloader. To do that see the trampoline examples.
This is how my AVR32 app usually looks like:
#include <avr32/io.h>
#include <stddef.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include "intc.c"
#include "gpio.c"
#include "pm_uc3l.c"
#include "scif_uc3l.c"
#include "adcifb.c"
#include "flashcdw.c"
#include "pdca.c"
//#include "pwma.c"
#include "tc.c"
#include "usart.c"
#include "eic.c"
#include "genclk.h"
#include "osc.c"
#include "dfll.c"
#include "sysclk.c"
#include "status_codes.h"
#include "cycle_counter.h"
#include "sleep.h"
#include "delay.c"
#define cpu_clk 30000000
#define _LED AVR32_PIN_PA04
void system_init()
{
delay_init(115000);
Disable_global_interrupt();
INTC_init_interrupts();
scif_start_rc120M();
delay_ms(100);
pm_set_clk_domain_div((pm_clk_domain_t)AVR32_PM_CLK_GRP_CPU,PM_CKSEL_DIVRATIO_4);
pm_set_clk_domain_div((pm_clk_domain_t)AVR32_PM_CLK_GRP_PBA,PM_CKSEL_DIVRATIO_4);
pm_set_clk_domain_div((pm_clk_domain_t)AVR32_PM_CLK_GRP_PBB,PM_CKSEL_DIVRATIO_4);
pm_set_clk_domain_div((pm_clk_domain_t)AVR32_PM_CLK_GRP_HSB,PM_CKSEL_DIVRATIO_4);
pm_set_all_cksel(SCIF_RC120M_FREQ_HZ,cpu_clk,cpu_clk,cpu_clk);
flashcdw_set_flash_waitstate_and_readmode(cpu_clk);
pm_set_mclk_source(PM_CLK_SRC_RC120M);
delay_init(cpu_clk);
}
//------------------------------------------------------------------------------------------------
void wait_ms(U32 dt)
{
U32 t0,t1;
t0=Get_system_register(AVR32_COUNT);
dt=((dt*cpu_clk)+999)/1000;
t0&=RDTSC_mask;
for (;;)
{
t1=Get_system_register(AVR32_COUNT);
t1&=RDTSC_mask;
if (t0>t1) t1+=RDTSC_mask+1;
if ((t1-t0)>=dt) break;
}
}
//------------------------------------------------------------------------------------------------
void wait_us(U32 dt)
{
U32 t0,t1;
t0=Get_system_register(AVR32_COUNT);
dt=((dt*cpu_clk)+999999)/1000000;
t0&=RDTSC_mask;
for (;;)
{
t1=Get_system_register(AVR32_COUNT);
t1&=RDTSC_mask;
if (t0>t1) t1+=RDTSC_mask+1;
if ((t1-t0)>=dt) break;
}
}
//------------------------------------------------------------------------------------------------
int main(void)
{
system_init();
// here init what you need
gpio_configure_pin(_LED,GPIO_DIR_OUTPUT|GPIO_INIT_HIGH);
for (;;)
{
// here do your stuff
gpio_tgl_gpio_pin(_LED);
wait_ms(200);
}
//------------------------------------------------------------------------------------------------
I do not use framework manager instead I include the stuff myself... and my framework is rewritten to avoid unnecessary includes and slowdowns of compilation. Also beware that framework updates are not always compatible so sometimes after update your code will not compile ... It is better to have one solid framework and not update it unless you really need to.
Select only the modules you need to (no need to include them all). For example you need intc,gpio,scif etc my includes are from bigger project so many of them are useless for you and also not all headers/modules are available for all of the AVR32 chips.
I got a bit off topic (I think was necessary) so back to GPIO
The API and architecture is completely changed. Do not be fooled by the pin names. For example pin PA35 does not mean port A pin 35 !!! There is no port PA It is just naming convention without any real meaning to the architecture which is a bit silly and took me a while to got along with it. There are as many ports as needed to cover all the pins. Each port support 32 pins and the pin number is the real thing you need to know.
Each pin is defined somewhere in avr32/io.h as a define like AVR32_PIN_PA04 and it contains numerical value of the pin position in chips GPIO. To obtain gpio port/mask you just do this:
port = pin>>5
mask = 1<<(pin&31)
Now to access GPIO registers directly I recommend to look at gpio.c. You can set,res,test,read 32 pins at a time to speed up (if they are at the same port). The speed is dependent mainly on the buss clock (usually PBA for GPIO) so if your clock for it is low do not expect high toggle rate. beware GPIO access is slow and if not used wisely can kill the performance of your code...
If HW pins selected for your App are done wisely you can have really fast speeds. For example I got toggle speeds around 2-5 MHz !!!
Here example of setting a pin from gpio.c
void gpio_set_gpio_pin(uint32_t pin)
{
U32 bit= 1 << (pin & 0x1F);
volatile avr32_gpio_port_t *gpio_port = &GPIO.port[pin >> 5];
gpio_port->ovrs = bit; // Value to be driven on the I/O line: 1.
gpio_port->oders = bit; // The GPIO output driver is enabled for that pin.
gpio_port->gpers = bit; // The GPIO module controls that pin.
}
You can use this to set multiple pins at the same port simply by exchanging bit with the mask of all pins you want to set ...
If you are using Interrupts for GPIO beware that the interrupt controller INTC is also a separate module connected by buss and wrongly set clock or wait states can cause huge problems.