Serial Baud Rates while using a 13192 SARD

[mjcoury]

I need to use a faster baud rate than 38400 and the faster baud rates are not reachable due to the math involved with the clock divider.

Has anyone had any success changing the clock speed coming out of the zigbee IC so I can achieve 115200 Baud on the HCS08?


Thanks,


MC

[peg]

Hi,

Haven't tried it but I guess you could try this:

Set the 13192 for 32k768 out

Configure the GT ICG to generate a 7.3728MHz buss from this.

Use /4 to get baudrate of 115200.

The clock rate of the MCU is only a little lower than before so you might get away with it.

Might try it myself one day...

Regards David

[UK_CF_FAE]

Hi,

I have 115200 baud working on the SARD/EVB boards, in fact I showed this working at the Manchester, UK MCF52235 Seminar today.

The My_Wireless_App.mcp demo that ships with the EVK software has a coordinator (Example 6a) that runs with a system clock of 16.78MHz. In NVRAM.c, the baudrate divider is set to 0x0009, to give a 115200 baud rate.

This examples sets register 0x0A in the MC1319x (CLKO) to give an output clock of 32.768 kHz, and uses the fll in the GT60 to make 16.78 MHz.

#ifdef SYSTEM_CLOCK_16_78MHZ
 0x10, // 16 MHz -> ~16,78 MHz
 //0x3646,
  (ABEL_XTAL_TRIM | ABEL_XTAL_BIAS_CURRENT | ABEL_CHIP_RATE | 6),
 (ABEL_CCA_ENERGY_DETECT_THRESHOLD | ABEL_POWER_COMPENSATION_OFFSET),
// ICG clock
 0x18,
 0x60, // 0x60 => CPU clk=32,78 MHz, Buc clk = 16,39 MHz
// ICG Filter
 0x02,
 0x40,
// SCI
 0x00,
 0x09, // 0x6D => 9600 @ 16,78 MHz ( 9,621 baud)
// 0x09, // 0x09 => 115200 @ 16,78 MHz
#endif SYSTEM_CLOCK_16_78MHZ

It works,

Mark

[mjcoury]

I was able to sucessfully get 15200 baud using the first example, thanks to both of you!

Message Edited by mjcoury on 2006-06-06 03:25 PM