Add beginTransaction to HAL SPI (#9019)

This commit is contained in:
revilor
2018-01-03 12:12:25 +01:00
committed by Scott Lahteine
parent fc67c64b8f
commit 959a2d2527
6 changed files with 122 additions and 3 deletions

View File

@ -1,4 +1,4 @@
/**
/*
* Marlin 3D Printer Firmware
* Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
*
@ -94,7 +94,9 @@ void spiBegin (void) {
SPCR = _BV(SPE) | _BV(MSTR) | (spiRate >> 1);
SPSR = spiRate & 1 || spiRate == 6 ? 0 : _BV(SPI2X);
}
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
/** SPI receive a byte */
uint8_t spiRec(void) {
SPDR = 0xFF;
@ -132,6 +134,72 @@ void spiBegin (void) {
}
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 == SPI_LSBFIRST) ? _BV(DORD) : 0) |
(dataMode << CPHA) | ((clockDiv >> 1) << SPR0);
SPSR = clockDiv | 0x01;
}
//------------------------------------------------------------------------------
#else // SOFTWARE_SPI
//------------------------------------------------------------------------------
@ -144,6 +212,12 @@ void spiBegin (void) {
UNUSED(spiRate);
}
/** Begin SPI transaction, set clock, bit order, data mode */
void spiBeginTransaction(uint32_t spiClock, uint8_t bitOrder, uint8_t dataMode) {
// nothing to do
UNUSED(spiBeginTransaction);
}
//------------------------------------------------------------------------------
/** Soft SPI receive byte */
uint8_t spiRec() {
@ -206,7 +280,7 @@ void spiBegin (void) {
spiSend(token);
for (uint16_t i = 0; i < 512; i++)
spiSend(buf[i]);
}
}
#endif // SOFTWARE_SPI