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Implement bitbang SPI for slow clock devices. (Sylvan Butler).

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This commit is contained in:
Peter Van Hoyweghen 2015-06-16 22:10:25 +02:00
parent a17a757722
commit 64e52d8016
1 changed files with 53 additions and 3 deletions
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56
build/shared/examples/11.ArduinoISP/ArduinoISP/ArduinoISP.ino
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@ -43,7 +43,6 @@
// - The SPI functions herein were developed for the AVR910_ARD programmer // - The SPI functions herein were developed for the AVR910_ARD programmer
// - More information at http://code.google.com/p/mega-isp // - More information at http://code.google.com/p/mega-isp
#include "SPI.h"
#include "pins_arduino.h" #include "pins_arduino.h"
// Use pin 10 to reset the target // Use pin 10 to reset the target
#define RESET 10 #define RESET 10
@ -53,6 +52,17 @@
#define LED_PMODE 7 #define LED_PMODE 7
#define PROG_FLICKER true #define PROG_FLICKER true
#if defined(ARDUINO_ARCH_SAM) or defined(ARDUINO_ARCH_SAMD)
#define SPI_CLOCK_DIV_MAX 255
#else
#define USE_HARDWARE_SPI
#define SPI_CLOCK_DIV_MAX SPI_CLOCK_DIV_128
#endif
#define HWVER 2 #define HWVER 2
#define SWMAJ 1 #define SWMAJ 1
#define SWMIN 18 #define SWMIN 18
@ -67,12 +77,52 @@
void pulse(int pin, int times); void pulse(int pin, int times);
#ifdef USE_HARDWARE_SPI
#include "SPI.h"
#else
class BitBangedSPI {
public:
void setDataMode(uint8_t dataMode) {
(void) dataMode;
}
void setBitOrder(uint8_t bitOrder) {
(void) bitOrder;
}
void setClockDivider(uint8_t clockDiv) {
(void) clockDiv;
}
void begin() {
pinMode(MISO, INPUT);
pinMode(RESET, OUTPUT);
pinMode(SCK, OUTPUT);
pinMode(MOSI, OUTPUT);
}
void end() {}
uint8_t transfer (uint8_t b) {
for (unsigned int i = 0; i < 8; ++i) {
digitalWrite(MOSI, b & 0x80);
digitalWrite(SCK, HIGH);
b = (b << 1) | digitalRead(MISO);
digitalWrite(SCK, LOW); // slow pulse
}
return b;
}
};
static BitBangedSPI SPI;
#endif
void setup() { void setup() {
Serial.begin(19200); Serial.begin(19200);
SPI.setDataMode(0); SPI.setDataMode(0);
SPI.setBitOrder(MSBFIRST); SPI.setBitOrder(MSBFIRST);
// Clock Div can be 2,4,8,16,32,64, or 128 // Select the slowest possible clock
SPI.setClockDivider(SPI_CLOCK_DIV128); SPI.setClockDivider(SPI_CLOCK_DIV_MAX);
pinMode(LED_PMODE, OUTPUT); pinMode(LED_PMODE, OUTPUT);
pulse(LED_PMODE, 2); pulse(LED_PMODE, 2);
pinMode(LED_ERR, OUTPUT); pinMode(LED_ERR, OUTPUT);