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spi.c
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spi.c
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/*****************************************************************************
* *
* DFU/SD/SDHC Bootloader for LPC17xx *
* *
* by Triffid Hunter *
* *
* *
* This firmware is Copyright (C) 2009-2010 Michael Moon aka Triffid_Hunter *
* *
* 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 program 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, write to the Free Software *
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA *
* *
*****************************************************************************/
#include "spi.h"
#include "lpc17xx_clkpwr.h"
#include "lpc17xx_pinsel.h"
#include "lpc17xx_ssp.h"
#include "lpc17xx_gpio.h"
#include <stdio.h>
// #define SOFT_SPI
uint32_t delay;
Pin_t miso;
Pin_t mosi;
Pin_t sclk;
SPI_REG *sspr;
void SPI_init(PinName mosi, PinName miso, PinName sclk)
{
FIO_SetDir((mosi >> 5) & 7, 1UL << (mosi & 0x1F), 1);
FIO_SetDir((miso >> 5) & 7, 1UL << (miso & 0x1F), 0);
FIO_SetDir((sclk >> 5) & 7, 1UL << (sclk & 0x1F), 1);
if (mosi == P0_9 && miso == P0_8 && sclk == P0_7)
{
// SSP1 on 0.7,0.8,0.9
sspr = LPC_SSP1;
// isr_dispatch[1] = this;
// printf("SPI:Using SSP1\n");
LPC_PINCON->PINSEL0 &= ~((3 << (7*2)) | (3 << (8*2)) | (3 << (9*2)));
LPC_PINCON->PINSEL0 |= ((2 << (7*2)) | (2 << (8*2)) | (2 << (9*2)));
LPC_SC->PCLKSEL0 &= 0xFFCFFFFF;
LPC_SC->PCLKSEL0 |= 0x00100000;
LPC_SC->PCONP |= CLKPWR_PCONP_PCSSP1;
}
else if (mosi == P0_18 && miso == P0_17 && sclk == P0_15)
{
// SSP0 on 0.15,0.16,0.17,0.18
sspr = LPC_SSP0;
// isr_dispatch[0] = this;
LPC_PINCON->PINSEL0 &= ~(3 << (15*2));
LPC_PINCON->PINSEL0 |= (2 << (15*2));
LPC_PINCON->PINSEL1 &= ~( (3 << ((17*2)&30)) | (3 << ((18*2)&30)) );
LPC_PINCON->PINSEL1 |= ( (2 << ((17*2)&30)) | (2 << ((18*2)&30)) );
LPC_SC->PCLKSEL1 &= 0xFFFFF3FF;
LPC_SC->PCLKSEL1 |= 0x00000400;
LPC_SC->PCONP |= CLKPWR_PCONP_PCSSP0;
}
else if (mosi == P1_24 && miso == P1_23 && sclk == P1_20)
{
// SSP0 on 1.20,1.23,1.24
sspr = LPC_SSP0;
// isr_dispatch[0] = this;
// // LPC_PINCON->PINSEL3 &= 0xFFFC3CFF;
// LPC_PINCON->PINSEL3 |= 0x0003C300;
// LPC_PINCON->PINSEL3 &= ~( (3 << ((20*2)&30)) | (3 << ((23*2)&30)) | (3 << ((24*2)&30)) );
LPC_PINCON->PINSEL3 |= ( (3 << ((20*2)&30)) | (3 << ((23*2)&30)) | (3 << ((24*2)&30)) );
LPC_SC->PCLKSEL1 &= 0xFFFFF3FF;
LPC_SC->PCLKSEL1 |= 0x00000400;
LPC_SC->PCONP |= CLKPWR_PCONP_PCSSP0;
}
else
{
sspr = (LPC_SSP_TypeDef *) 0;
}
if (sspr) {
sspr->CR0 = SSP_DATABIT_8 |
SSP_FRAME_SPI;
sspr->CR1 = SSP_MASTER_MODE;
SPI_frequency(10000);
sspr->CR1 |= SSP_CR1_SSP_EN;
}
}
void SPI_frequency(uint32_t f)
{
// CCLK = 25MHz
// CPSR = 2 to 254, even only
// CR0[8:15] (SCR, 0..255) is a further prescale
// iprintf("SPI: frequency %lu:", f);
delay = 25000000 / f;
// f = 25MHz / (CPSR . [SCR + 1])
// CPSR . (SCR + 1) = 25MHz / f
// min freq is 25MHz / (254 * 256)
if (sspr) {
if (f < 385) {
sspr->CPSR = 254;
sspr->CR0 &= 0x00FF;
sspr->CR0 |= 255 << 8;
}
// max freq is 25MHz / (2 * 1)
else if (f > 12500000) {
sspr->CPSR = 2;
sspr->CR0 &= 0x00FF;
}
else {
sspr->CPSR = delay & 0xFE;
// CPSR . (SCR + 1) = f;
// (SCR + 1) = f / CPSR;
// SCR = (f / CPSR) - 1
sspr->CR0 &= 0x00FF;
sspr->CR0 |= (((delay / sspr->CPSR) - 1) & 0xFF) << 8;
}
// iprintf(" CPSR=%lu, CR0=%lu", sspr->CPSR, sspr->CR0);
}
// iprintf("\n");
}
void _delay(uint32_t ticks) {
for (;ticks;ticks--)
asm volatile("nop\n\t");
}
uint8_t SPI_write(uint8_t data)
{
// _cs = 1;
uint8_t r = 0;
// printf("SPI: >0x%x", data);
if (sspr) {
while ((sspr->SR & SSP_SR_TNF) == 0);
sspr->DR = data;
while ((sspr->SR & SSP_SR_RNE) == 0);
r = sspr->DR & 255;
}
#ifdef SOFT_SPI
else {
for (int i = 0; i < 8; i++) {
FIO_ClearValue(sclk.port, 1UL << sclk.pin); // clock LOW
if (data & 0x80) // WRITE
FIO_SetValue(mosi.port, 1UL << mosi.pin);
else
FIO_ClearValue(mosi.port, 1UL << mosi.pin);
data <<= 1;
_delay(delay >> 1); // DELAY
FIO_SetValue(sclk.port, 1UL << sclk.pin); // clock HIGH
_delay(delay >> 1); // DELAY
r <<= 1;
if (FIO_ReadValue(miso.port) & (1UL << miso.pin)) // READ
r |= 1;
}
FIO_ClearValue(sclk.port, 1UL << sclk.pin);
}
#endif
// printf(" <0x%x\n", r);
return r;
}
// TODO: timer feeds DMA feeds 0xFFs to card then we listen for responses using our interrupt
// allow me to do something like:
// disk.start_multi_write(int blocks, int blocksize, void *buffer);
// enable_usb_isr();
// [...]
// usb_isr() {
// if (disk.buffer_in_use(void *buffer))
// return;
// usb_ep_read(buffer);
// if (buffer_full)
// disk.validate_buffer(buffer);
// if (disk.finished_transfer())
// disk.end_multi_write();
// };
// bool SPI_can_DMA()
// {
// return (sspr != NULL);
// }
// int SPI::setup_DMA_rx(DMA_REG *dma)
// {
// if (!sspr)
// return -1;
//
// dma->DMACCControl = 0;
// dma->DMACCConfiguration = 0;
// if (sspr == LPC_SSP0)
// dma->DMACCConfiguration |= (GPDMA_CONN_SSP0_Rx << 6);
// if (sspr == LPC_SSP1)
// dma->DMACCConfiguration |= (GPDMA_CONN_SSP1_Rx << 6);
//
// dma->DMACCConfiguration |= GPDMA_TRANSFERTYPE_M2P << 11;
// return 0;
// }
//
// int SPI::start_DMA_rx(DMA_REG *dma)
// {
// dma->DMACCConfiguration |=
// }
// int SPI_writeblock(uint8_t *block, int blocklen)
// {
// static DMA *d = new DMA();
// d.sourceaddr(block);
// d.transferlength(blocklen);
// d.destinationperipheral(sspr);
// d.start();
// while (d.active());
// return blocklen;
// return 0;
// }
// void SPI_irq()
// {
// }
// void SSP0_IRQHandler(void) {
// if (isr_dispatch[0])
// isr_dispatch[0]();
// }
// void SSP1_IRQHandler(void) {
// if (isr_dispatch[1])
// isr_dispatch[1]();
// }