projects / sigrok-dumps.git / blame
| Commit | Line | Data |
|---|---|---|
| 8f2d2918 UH |
1 | ------------------------------------------------------------------------------- |
| 2 | SPI / Atmel ATMEGA32 | |
| 3 | ------------------------------------------------------------------------------- | |
| 4 | ||
| 5 | This is a set of SPI captures from an Atmel ATMEGA32 device. The main loop of | |
| 6 | the C program outputs an 8-bit value which is increased by one between | |
| 7 | subsequent transmissions: | |
| 8 | ||
| 9 | unsigned char c = 0; | |
| 10 | for (;;) { | |
| 11 | _delay_us(250); | |
| 12 | cbi(PORTB, DD_SS); | |
| 13 | SPDR = c; | |
| 14 | c++; | |
| 15 | while (!(SPSR & (1 << SPIF))); | |
| 16 | sbi(PORTB, DD_SS); | |
| 17 | } | |
| 18 | ||
| 19 | ||
| 20 | Logic analyzer setup | |
| 21 | -------------------- | |
| 22 | ||
| 23 | The logic analyzer used was a Saleae Logic (at 500kHz). | |
| 24 | ||
| 25 | Probe ATMEGA32 pins (PDIP-40) | |
| 26 | --------------------------------- | |
| 27 | 0 (CS) SS/PB4 (Pin 5) | |
| 28 | 1 (MOSI) MOSI/PB5 (Pin 6) | |
| 29 | 2 (SCK) SCK/PB7 (Pin 8) | |
| 30 | ||
| 31 | ||
| 32 | Probing | |
| 33 | ------- | |
| 34 | ||
| 35 | The sigrok command line used was: | |
| 36 | ||
| 37 | sigrok-cli --driver fx2lafw --samples=1m --config samplerate=500k -o <file> | |
| 38 | ||
| 39 | ||
| 40 | SPI setup | |
| 41 | --------- | |
| 42 | ||
| 43 | There are 4 different SPI setups each captured in a separate capture file | |
| 44 | (see the ATMEGA datasheet for the meaning of the CPOL & CPHA flags). | |
| 45 | ||
| 46 | ||
| 47 | spi_atmega32_00.sr | |
| 48 | ------------------ | |
| 49 | ||
| 50 | SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR0)|(1<<SPR1); | |
| 51 | ||
| 52 | ||
| 53 | spi_atmega32_11.sr | |
| 54 | ------------------ | |
| 55 | ||
| 56 | SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR0)|(1<<SPR1) | (1<<CPOL) | (1<<CPHA); | |
| 57 | ||
| 58 | ||
| 59 | spi_atmega32_01.sr | |
| 60 | ------------------ | |
| 61 | ||
| 62 | SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR0)|(1<<SPR1) | (1<<CPHA); | |
| 63 | ||
| 64 | ||
| 65 | spi_atmega32_10.sr | |
| 66 | ------------------ | |
| 67 | ||
| 68 | SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR0)|(1<<SPR1) | (1<<CPOL); | |
| 69 |