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f32xbase/f32x/c2-bitbang.c
Werner Almesberger 6a4da0eaef Moved C2 bitbang functions from c2-om.c to (#included) c2-bitbang.c
- f32x/c2-om.c: renamed C2 bitbang functions from om_* to c2_*
- f32x/c2-om.c,  f32x/c2-bitbang.c: moved most of the content of c2-om.c to
  c2-bitbang.c and #include c2-bitbang.c
- f32x/Makefile: c2-om.o depends on c2-bitbang.c now
2010-10-21 19:09:43 -03:00

128 lines
2.1 KiB
C

/*
* f32x/c2-bitbang.c - Basic C2 messages, bitbang
*
* Written 2008, 2010 by Werner Almesberger
* Copyright 2008, 2010 Werner Almesberger
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
/*
* This file is meant to be #included by a .c file that defines C2CK and C2D,
* provides the gpio_* functions, etc.
*/
/* ----- Bit-level operations ---------------------------------------------- */
static void c2_pulse(void)
{
gpio_low(C2CK);
gpio_high(C2CK);
}
static void c2_send(uint32_t value, int bits)
{
int i;
for (i = 0; i != bits; i++) {
gpio_set(C2D, (value >> i) & 1);
c2_pulse();
}
}
static uint32_t c2_recv(int bits)
{
uint32_t v = 0;
int i;
for (i = 0; i != bits; i++) {
v |= gpio_get(C2D) << i;
c2_pulse();
}
return v;
}
/* ----- C2 Register read/write -------------------------------------------- */
static void c2_addr_write(uint8_t addr)
{
c2_pulse();
gpio_output(C2D);
c2_send(C2_ADDR_WRITE, 2);
c2_send(addr, 8);
gpio_input(C2D);
c2_pulse();
}
static uint8_t c2_addr_read(void)
{
c2_pulse();
gpio_output(C2D);
c2_send(C2_ADDR_READ, 2);
gpio_input(C2D);
c2_pulse();
return c2_recv(8);
}
static void c2_data_write(uint32_t data, int bytes)
{
c2_pulse();
gpio_output(C2D);
c2_send(C2_DATA_WRITE, 2);
c2_send(bytes-1, 2);
c2_send(data, 8*bytes);
gpio_input(C2D);
c2_pulse();
while (!c2_recv(1));
}
static uint32_t c2_data_read(int bytes)
{
c2_pulse();
gpio_output(C2D);
c2_send(C2_DATA_READ, 2);
c2_send(bytes-1, 2);
gpio_input(C2D);
c2_pulse();
while (!c2_recv(1));
return c2_recv(8*bytes);
}
/* ----- C2 initialization ------------------------------------------------- */
static void c2_init(void)
{
gpio_init();
gpio_input(C2D);
gpio_output(C2CK);
gpio_low(C2CK);
usleep(20);
gpio_high(C2CK);
usleep(2);
}
static void c2_reset(void)
{
gpio_input(C2D);
gpio_low(C2CK);
usleep(20);
// gpio_input(C2CK);
gpio_output(C2CK);
gpio_high(C2CK);
}