Firmware2/Marlin/src/HAL/AVR/HAL_SPI.cpp
2020-03-13 23:18:16 -05:00

254 lines
6.6 KiB
C++

/**
* Marlin 3D Printer Firmware
* Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
*
* Based on Sprinter and grbl.
* Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
*/
/**
* Adapted from Arduino Sd2Card Library
* Copyright (c) 2009 by William Greiman
*/
/**
* HAL for AVR - SPI functions
*/
#ifdef __AVR__
#include "../../inc/MarlinConfig.h"
void spiBegin() {
OUT_WRITE(SS_PIN, HIGH);
SET_OUTPUT(SCK_PIN);
SET_INPUT(MISO_PIN);
SET_OUTPUT(MOSI_PIN);
#if DISABLED(SOFTWARE_SPI)
// SS must be in output mode even it is not chip select
//SET_OUTPUT(SS_PIN);
// set SS high - may be chip select for another SPI device
//#if SET_SPI_SS_HIGH
//WRITE(SS_PIN, HIGH);
//#endif
// set a default rate
spiInit(1);
#endif
}
#if NONE(SOFTWARE_SPI, FORCE_SOFT_SPI)
// ------------------------
// Hardware SPI
// ------------------------
// make sure SPCR rate is in expected bits
#if (SPR0 != 0 || SPR1 != 1)
#error "unexpected SPCR bits"
#endif
/**
* Initialize hardware SPI
* Set SCK rate to F_CPU/pow(2, 1 + spiRate) for spiRate [0,6]
*/
void spiInit(uint8_t spiRate) {
// See avr processor documentation
CBI(
#ifdef PRR
PRR
#elif defined(PRR0)
PRR0
#endif
, PRSPI);
SPCR = _BV(SPE) | _BV(MSTR) | (spiRate >> 1);
SPSR = spiRate & 1 || spiRate == 6 ? 0 : _BV(SPI2X);
}
/** SPI receive a byte */
uint8_t spiRec() {
SPDR = 0xFF;
while (!TEST(SPSR, SPIF)) { /* Intentionally left empty */ }
return SPDR;
}
/** SPI read data */
void spiRead(uint8_t* buf, uint16_t nbyte) {
if (nbyte-- == 0) return;
SPDR = 0xFF;
for (uint16_t i = 0; i < nbyte; i++) {
while (!TEST(SPSR, SPIF)) { /* Intentionally left empty */ }
buf[i] = SPDR;
SPDR = 0xFF;
}
while (!TEST(SPSR, SPIF)) { /* Intentionally left empty */ }
buf[nbyte] = SPDR;
}
/** SPI send a byte */
void spiSend(uint8_t b) {
SPDR = b;
while (!TEST(SPSR, SPIF)) { /* Intentionally left empty */ }
}
/** SPI send block */
void spiSendBlock(uint8_t token, const uint8_t* buf) {
SPDR = token;
for (uint16_t i = 0; i < 512; i += 2) {
while (!TEST(SPSR, SPIF)) { /* Intentionally left empty */ }
SPDR = buf[i];
while (!TEST(SPSR, SPIF)) { /* Intentionally left empty */ }
SPDR = buf[i + 1];
}
while (!TEST(SPSR, SPIF)) { /* Intentionally left empty */ }
}
/** begin spi transaction */
void spiBeginTransaction(uint32_t spiClock, uint8_t bitOrder, uint8_t dataMode) {
// Based on Arduino SPI library
// Clock settings are defined as follows. Note that this shows SPI2X
// inverted, so the bits form increasing numbers. Also note that
// fosc/64 appears twice
// SPR1 SPR0 ~SPI2X Freq
// 0 0 0 fosc/2
// 0 0 1 fosc/4
// 0 1 0 fosc/8
// 0 1 1 fosc/16
// 1 0 0 fosc/32
// 1 0 1 fosc/64
// 1 1 0 fosc/64
// 1 1 1 fosc/128
// We find the fastest clock that is less than or equal to the
// given clock rate. The clock divider that results in clock_setting
// is 2 ^^ (clock_div + 1). If nothing is slow enough, we'll use the
// slowest (128 == 2 ^^ 7, so clock_div = 6).
uint8_t clockDiv;
// When the clock is known at compiletime, use this if-then-else
// cascade, which the compiler knows how to completely optimize
// away. When clock is not known, use a loop instead, which generates
// shorter code.
if (__builtin_constant_p(spiClock)) {
if (spiClock >= F_CPU / 2) clockDiv = 0;
else if (spiClock >= F_CPU / 4) clockDiv = 1;
else if (spiClock >= F_CPU / 8) clockDiv = 2;
else if (spiClock >= F_CPU / 16) clockDiv = 3;
else if (spiClock >= F_CPU / 32) clockDiv = 4;
else if (spiClock >= F_CPU / 64) clockDiv = 5;
else clockDiv = 6;
}
else {
uint32_t clockSetting = F_CPU / 2;
clockDiv = 0;
while (clockDiv < 6 && spiClock < clockSetting) {
clockSetting /= 2;
clockDiv++;
}
}
// Compensate for the duplicate fosc/64
if (clockDiv == 6) clockDiv = 7;
// Invert the SPI2X bit
clockDiv ^= 0x1;
SPCR = _BV(SPE) | _BV(MSTR) | ((bitOrder == LSBFIRST) ? _BV(DORD) : 0) |
(dataMode << CPHA) | ((clockDiv >> 1) << SPR0);
SPSR = clockDiv | 0x01;
}
#else // SOFTWARE_SPI || FORCE_SOFT_SPI
// ------------------------
// Software SPI
// ------------------------
// nop to tune soft SPI timing
#define nop asm volatile ("\tnop\n")
void spiInit(uint8_t) { /* do nothing */ }
// Begin SPI transaction, set clock, bit order, data mode
void spiBeginTransaction(uint32_t spiClock, uint8_t bitOrder, uint8_t dataMode) { /* do nothing */ }
// Soft SPI receive byte
uint8_t spiRec() {
uint8_t data = 0;
// no interrupts during byte receive - about 8µs
cli();
// output pin high - like sending 0xFF
WRITE(MOSI_PIN, HIGH);
LOOP_L_N(i, 8) {
WRITE(SCK_PIN, HIGH);
nop; // adjust so SCK is nice
nop;
data <<= 1;
if (READ(MISO_PIN)) data |= 1;
WRITE(SCK_PIN, LOW);
}
sei();
return data;
}
// Soft SPI read data
void spiRead(uint8_t* buf, uint16_t nbyte) {
for (uint16_t i = 0; i < nbyte; i++)
buf[i] = spiRec();
}
// Soft SPI send byte
void spiSend(uint8_t data) {
// no interrupts during byte send - about 8µs
cli();
LOOP_L_N(i, 8) {
WRITE(SCK_PIN, LOW);
WRITE(MOSI_PIN, data & 0x80);
data <<= 1;
WRITE(SCK_PIN, HIGH);
}
nop; // hold SCK high for a few ns
nop;
nop;
nop;
WRITE(SCK_PIN, LOW);
sei();
}
// Soft SPI send block
void spiSendBlock(uint8_t token, const uint8_t* buf) {
spiSend(token);
for (uint16_t i = 0; i < 512; i++)
spiSend(buf[i]);
}
#endif // SOFTWARE_SPI || FORCE_SOFT_SPI
#endif // __AVR__