111 lines
2.7 KiB
C
111 lines
2.7 KiB
C
/*
|
|
ChibiOS/RT - Copyright (C) 2006-2007 Giovanni Di Sirio.
|
|
|
|
This file is part of ChibiOS/RT.
|
|
|
|
ChibiOS/RT 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 3 of the License, or
|
|
(at your option) any later version.
|
|
|
|
ChibiOS/RT is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#include <ch.h>
|
|
|
|
#include "lpc214x.h"
|
|
#include "lpc214x_SSP.h"
|
|
|
|
#ifdef SSP_USE_MUTEX
|
|
static Semaphore me;
|
|
#endif
|
|
|
|
void sspAcquireBus(void) {
|
|
|
|
#ifdef SSP_USE_MUTEX
|
|
chSemWait(&me);
|
|
#endif
|
|
IO0CLR = 1 << 20;
|
|
}
|
|
|
|
void sspReleaseBus(void) {
|
|
|
|
IO0SET = 1 << 20;
|
|
#ifdef SSP_USE_MUTEX
|
|
chSemSignal(&me);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Synchronous SSP transfer.
|
|
* @param in pointer to the incoming data buffer, if this parameter is set to
|
|
* \p NULL then the incoming data is discarded.
|
|
* @param out pointer to the outgoing data buffer, if this parameter is set to
|
|
* \p NULL then 0xFF bytes will be output.
|
|
* @param n the number of bytes to be transferred
|
|
* @note The transfer is performed in a software loop and is not interrupt
|
|
* driven for performance reasons, this function should be invoked
|
|
* by a low priority thread in order to "play nice" with the
|
|
* rest of the system. This kind of peripheral would really need a
|
|
* dedicated DMA channel.
|
|
*/
|
|
void sspRW(uint8_t *in, uint8_t *out, t_size n) {
|
|
int icnt, ocnt;
|
|
|
|
SSP *ssp = SSPBase;
|
|
icnt = ocnt = n;
|
|
while (icnt) {
|
|
|
|
if (ssp->SSP_SR & SR_RNE) {
|
|
if (in)
|
|
*in++ = ssp->SSP_DR;
|
|
else
|
|
ssp->SSP_DR;
|
|
icnt--;
|
|
continue; /* Priority over transmission. */
|
|
}
|
|
|
|
if (ocnt && (ssp->SSP_SR & SR_TNF)) {
|
|
if (out)
|
|
ssp->SSP_DR = *out++;
|
|
else
|
|
ssp->SSP_DR = 0xFF;
|
|
ocnt--;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* SSP setup.
|
|
*/
|
|
void SetSSP(int cpsr, int cr0, int cr1) {
|
|
|
|
SSP *ssp = SSPBase;
|
|
ssp->SSP_CR1 = 0;
|
|
ssp->SSP_CR0 = cr0;
|
|
ssp->SSP_CPSR = cpsr;
|
|
ssp->SSP_CR1 = cr1 | CR1_SSE;
|
|
}
|
|
|
|
/*
|
|
* SSP subsystem initialization.
|
|
*/
|
|
void InitSSP(void) {
|
|
|
|
/* Enables the SPI1 clock */
|
|
PCONP = (PCONP & PCALL) | PCSPI1;
|
|
|
|
/* Clock = PCLK / 2 (fastest). */
|
|
SetSSP(2, CR0_DSS8BIT | CR0_FRFSPI | CR0_CLOCKRATE(0), 0);
|
|
|
|
#ifdef SSP_USE_MUTEX
|
|
chSemInit(&me, 1);
|
|
#endif
|
|
}
|