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using PCA FOR baud rate generation i am acing problem

HEllo we are using silabs c8051f340 controller.we try to implement software uart using programle counter arrays(PCA)for baud rate generation and i am not able get to desired baudrate .we are using internal clk of 12000000 and baudrate is 9600 please try to give sloution

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0 stephen phillips over 17 years ago in reply to chandra vel

Wow that came out to one line this is kind of what it was supposed to be I think.

void UART0_Init (void)
{
SCON0 = 0x10; // SCON0: 8-bit variable bit rate
// level of STOP bit is ignored
// RX enabled
// ninth bits are zeros
// clear RI0 and TI0 bits
if (SYSCLK/BAUDRATE/2/256 < 1) {
TH1 = -(SYSCLK/BAUDRATE/2);
CKCON &= ~0x0B; // T1M = 1;
SCA1:0 = xx CKCON |= 0x08;
}
else
if (SYSCLK/BAUDRATE/2/256 < 4)
{
TH1 = -(SYSCLK/BAUDRATE/2/4);
CKCON &= ~0x0B; // T1M = 0; SCA1:0 = 01
CKCON |= 0x09;
}
else
if (SYSCLK/BAUDRATE/2/256 < 12)
{
TH1 = -(SYSCLK/BAUDRATE/2/12);
CKCON &= ~0x0B;
// T1M = 0; SCA1:0 = 00
}
else
{
TH1 = -(SYSCLK/BAUDRATE/2/48);
CKCON &= ~0x0B;
// T1M = 0; SCA1:0 = 10
CKCON |= 0x02;
}

TL1 = TH1; // init Timer1
TMOD &= ~0xf0; // TMOD: timer 1 in 8-bit autoreload
TMOD |= 0x20;
TR1 = 1; // START Timer1
TI0 = 1; // Indicate TX0 ready
}

Dubious translation caveats added.

Stephen

Reply

0 stephen phillips over 17 years ago in reply to chandra vel

Wow that came out to one line this is kind of what it was supposed to be I think.

void UART0_Init (void)
{
SCON0 = 0x10; // SCON0: 8-bit variable bit rate
// level of STOP bit is ignored
// RX enabled
// ninth bits are zeros
// clear RI0 and TI0 bits
if (SYSCLK/BAUDRATE/2/256 < 1) {
TH1 = -(SYSCLK/BAUDRATE/2);
CKCON &= ~0x0B; // T1M = 1;
SCA1:0 = xx CKCON |= 0x08;
}
else
if (SYSCLK/BAUDRATE/2/256 < 4)
{
TH1 = -(SYSCLK/BAUDRATE/2/4);
CKCON &= ~0x0B; // T1M = 0; SCA1:0 = 01
CKCON |= 0x09;
}
else
if (SYSCLK/BAUDRATE/2/256 < 12)
{
TH1 = -(SYSCLK/BAUDRATE/2/12);
CKCON &= ~0x0B;
// T1M = 0; SCA1:0 = 00
}
else
{
TH1 = -(SYSCLK/BAUDRATE/2/48);
CKCON &= ~0x0B;
// T1M = 0; SCA1:0 = 10
CKCON |= 0x02;
}

TL1 = TH1; // init Timer1
TMOD &= ~0xf0; // TMOD: timer 1 in 8-bit autoreload
TMOD |= 0x20;
TR1 = 1; // START Timer1
TI0 = 1; // Indicate TX0 ready
}

Dubious translation caveats added.

Stephen

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