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Message |
fastlink30
Joined: 14 May 2007
Posts: 33
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| TRIS C |
 Posted: Mon Jun 04, 2007 4:19 am |
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16f877 pcwh 4.033
why after set_tris_c() the result is 0?
i use pn c6/7 for serial i/o and fast i/o.
| Code: |
void main() {
int8 car;
int16 tmp;
int8 mot;
char buff[6];
setup_adc_ports(NO_ANALOGS);
setup_adc(ADC_OFF);
setup_psp(PSP_DISABLED);
setup_spi(SPI_SS_DISABLED);
setup_timer_0(RTCC_INTERNAL|RTCC_DIV_1);
setup_timer_2(T2_DISABLED,0,1);
port_b_pullups(FALSE);
set_tris_a(0b00000000);
set_tris_b(0b00000000);
set_tris_c(0b10000000);// 0 = output
printf("%u \r",get_tris_c());
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fastlink30
Joined: 14 May 2007
Posts: 33
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| Posted: Tue Jun 05, 2007 10:18 am |
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i tried also
| Code: |
set_tris_b(0b10000011);
set_tris_c(0b10000011);
printf("[%u %u] \r",get_tris_b(),get_tris_c());
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result:
[131 0]
set_Tris_c() seems dont change value
where i'm wrong? maybe i don't disable somethng? |
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fastlink30
Joined: 14 May 2007
Posts: 33
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| Posted: Tue Jun 05, 2007 10:33 am |
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found the problem!
if i hide
#use fast_io(C)
all work ok.... but why? i can't use fast_io on port c? |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Jun 05, 2007 12:23 pm |
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In fast_io mode, the get_tris_c() function returns 0. It doesn't read
the TRISC register or a shadow register. It just returns 0. That's a bug.
Here's the ASM code produced for fast_io mode.
Notice that it loads W with 0x00 and then puts
W into 'tmp'.
| Code: |
... set_tris_c(0b10000000);
000D: MOVLW 80
000E: MOVWF 07 // TRISC = 0x80
... tmp = get_tris_c();
000F: MOVF 00,W // W = 0x00
0010: BCF 03.5 // Bank 0
0011: MOVWF 21 // tmp = W (tmp = 0x00)
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But it works OK for Port B:
| Code: |
... set_tris_b(0b10000000);
0012: MOVLW 80
0013: BSF 03.5
0014: MOVWF 06 // TRISB = 0x80
... tmp = get_tris_b();
0015: MOVF 06,W // Read TRISB
0016: BCF 03.5
0017: MOVWF 21 // Put it into 'tmp'
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Reading TRISC works OK if you don't enable fast_io mode
for Port C. Then it reads the TRIS from the Shadow register.
| Code: |
... set_tris_c(0b10000000);
000D: MOVLW FF
000E: BCF 03.5
000F: MOVWF 20
0010: MOVLW 80
0011: BSF 03.5
0012: MOVWF 07
0013: BCF 03.5
0014: MOVWF 20
... tmp = get_tris_c();
0015: MOVF 20,W // Read shadow reg. for TRISC
0016: MOVWF 21 // and put it in 'tmp'
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It also does this with vs. 4.040. |
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fastlink30
Joined: 14 May 2007
Posts: 33
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| Posted: Tue Jun 05, 2007 12:54 pm |
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aha, thank you for the info,now understand
strange ccs haven't fixed this problem |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Jun 05, 2007 1:04 pm |
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| They may not know about it. Report the bug to CCS tech support. |
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fastlink30
Joined: 14 May 2007
Posts: 33
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| Posted: Thu Jun 07, 2007 10:26 am |
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i do
they reported this bug will be solved in the next release |
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