mirror of
git://projects.qi-hardware.com/f32xbase.git
synced 2024-11-27 17:56:16 +02:00
80a0152663
- f32x/c2-om.c: moved system includes to c2-bitbang.c - f32x/c2-bitbang.c (c2_init): leave it to the upper layer to call gpio_init - f32x/c2-om.c (om_init): call gpio_init, then c2_init
131 lines
2.1 KiB
C
131 lines
2.1 KiB
C
/*
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* f32x/c2-bitbang.c - Basic C2 messages, bitbang
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*
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* Written 2008, 2010 by Werner Almesberger
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* Copyright 2008, 2010 Werner Almesberger
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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/*
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* This file is meant to be #included by a .c file that defines C2CK and C2D,
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* provides the gpio_* functions, etc.
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*/
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#include <stdint.h>
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#include <unistd.h>
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/* ----- Bit-level operations ---------------------------------------------- */
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static void c2_pulse(void)
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{
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gpio_low(C2CK);
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gpio_high(C2CK);
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}
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static void c2_send(uint32_t value, int bits)
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{
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int i;
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for (i = 0; i != bits; i++) {
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gpio_set(C2D, (value >> i) & 1);
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c2_pulse();
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}
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}
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static uint32_t c2_recv(int bits)
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{
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uint32_t v = 0;
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int i;
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for (i = 0; i != bits; i++) {
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v |= gpio_get(C2D) << i;
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c2_pulse();
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}
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return v;
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}
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/* ----- C2 Register read/write -------------------------------------------- */
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static void c2_addr_write(uint8_t addr)
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{
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c2_pulse();
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gpio_output(C2D);
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c2_send(C2_ADDR_WRITE, 2);
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c2_send(addr, 8);
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gpio_input(C2D);
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c2_pulse();
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}
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static uint8_t c2_addr_read(void)
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{
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c2_pulse();
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gpio_output(C2D);
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c2_send(C2_ADDR_READ, 2);
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gpio_input(C2D);
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c2_pulse();
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return c2_recv(8);
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}
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static void c2_data_write(uint32_t data, int bytes)
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{
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c2_pulse();
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gpio_output(C2D);
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c2_send(C2_DATA_WRITE, 2);
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c2_send(bytes-1, 2);
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c2_send(data, 8*bytes);
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gpio_input(C2D);
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c2_pulse();
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while (!c2_recv(1));
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}
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static uint32_t c2_data_read(int bytes)
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{
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c2_pulse();
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gpio_output(C2D);
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c2_send(C2_DATA_READ, 2);
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c2_send(bytes-1, 2);
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gpio_input(C2D);
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c2_pulse();
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while (!c2_recv(1));
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return c2_recv(8*bytes);
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}
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/* ----- C2 initialization ------------------------------------------------- */
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static void c2_init(void)
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{
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gpio_input(C2D);
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gpio_output(C2CK);
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gpio_low(C2CK);
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usleep(20);
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gpio_high(C2CK);
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usleep(2);
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}
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static void c2_reset(void)
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{
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gpio_input(C2D);
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gpio_low(C2CK);
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usleep(20);
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// gpio_input(C2CK);
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gpio_output(C2CK);
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gpio_high(C2CK);
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}
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