View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0032339 | FPC | RTL | public | 2017-08-26 19:32 | 2019-04-18 11:47 |
| Reporter | Christo Crause | Assigned To | |||
| Priority | normal | Severity | minor | Reproducibility | always |
| Status | new | Resolution | open | ||
| Product Version | 3.1.1 | Product Build | 36879 | ||
| Target Version | Fixed in Version | ||||
| Summary | 0032339: AVR - Incorrect SPI clock rate bit constant names in some microcontroller units | ||||
| Description | In some microcontroller unit files the constants for the bit positions SPR1 and SPR0 are incorrectly specified as: SPR = 0; // SPI Clock Rate Selects Typically two bits are used to select the clock frequency for SPI: SPR1 = 1; // SPI Clock Rate Selects SPR0 = 0; // SPI Clock Rate Selects I have fixed these constants everywhere I could find "SPR = 0", see attached patch. | ||||
| Tags | AVR | ||||
| Fixed in Revision | |||||
| FPCOldBugId | |||||
| FPCTarget | |||||
| Attached Files |
| ||||
|
|
avrrtlpatch.dif (52,179 bytes) |
|
|
I don't think this change is a good idea. The current format of the constants encode bit positions with the constant pointing to the index of the LSB of multi-bit fields. Ex. WGM0 in TCCR0A |
|
|
I noticed this issue because I was translating a C example from the atmega328p datasheet (end of section 18.2): /* Enable SPI, Master, set clock rate fck/16 */ SPCR = (1<<SPE)|(1<<MSTR)|(1<<SPR0); It is confusing for me if the naming convention mostly follow avr-gcc / Atmel, but then in a few cases differ. I think that compatibility with datasheet examples is important. It is still possible to set two consecutive bits with one shift instruction, by referring to bit 0: SPCR := 3 shl SPR0; // clock div 128 |
|
|
After this issue was unanswered for a while, I decided to play around with importing the atdf files. After a very interesting discussion on the Lazarus forum (http://forum.lazarus-ide.org/index.php/topic,38809.0.html) I added bitpacked record and set definitions of the peripheral registers to the processor definition files, in addition to the regular bit constants. Not sure what the core team's opinion is ? |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2017-08-26 19:32 | Christo Crause | New Issue | |
| 2017-08-26 19:32 | Christo Crause | File Added: avrrtlpatch.dif | |
| 2017-08-26 19:32 | Christo Crause | Tag Attached: AVR | |
| 2017-12-29 12:38 | Jeppe Johansen | Note Added: 0105103 | |
| 2017-12-31 07:38 | Christo Crause | Note Added: 0105177 | |
| 2017-12-31 07:51 | Christo Crause | Note Added: 0105178 |
