XE8805 SEMTECH [Semtech Corporation], XE8805 Datasheet - Page 76

• Manufacturer Part Number: XE8805
• Description: Data Acquisition MCU
• Manufacturer: SEMTECH [Semtech Corporation]

14.4 Interrupts map
14.5 Uart baud rate selection
In order to have correct baud rates, the Uart interface has to be fed with a stable and trimmed clock source. The
clock source can be the RC oscillator or the crystal oscillator. The precision of the baud rate will depend on the
precision of the selected clock source.
14.5.1
To select the RC oscillator for the Uart, the bit SelXtal in RegUartCmd has to be 0.
In order to obtain a correct baud rate, the RC oscillator frequency has to be set to one of the frequencies given in
the table on the next page. The precision of the obtained baud rate is directly proportional to the frequency
deviation with respect to the values in the table.
© Semtech 2006
pos.
pos.
pos.
7-2
7-0
7-6
1
0
5
4
3
2
1
0
Uart on the RC oscillator
RegUartRxSta
RegUartTxSta
UartRxBusy
UartTxBusy
RegUartRx
UartRxOErr
UartRxSErr
UartRxPErr
UartRxFErr
UartRxFull
UartTxFull
UartRx
-
-
Irq_uart_Tx
Irq_uart_Rx
interrupt source
rw
rw
rw
rc
r
r
r
r
r
r
r
r
r
r
0 resetsystem
0 resetsystem
0 resetsystem
0 resetsystem
0 resetsystem
0 resetsystem
0 resetsystem
0 resetsystem
Table 14-7: Interrupts map
Table 14-6: RegUartRxSta
Table 14-4: RegUartTxSta
resetsystem
IrqHig(1)
IrqHig(0)
00000000
Table 14-5: RegUartRx
default mapping in the interrupt manager
000000
Reset
reset
reset
00
14-3
Cleared when transferring RegUartTx into
Cleared by writing RegUartRxSta
Cleared by reading RegUartRx
Set by writing to RegUartTx
Uart busy transmitting
internal shift register
Uart busy receiving
RegUartRx full
RegUartTx full
Received data
Overrun error
description
description
description
Frame error
Parity error
Start error
Unused
Unused
XE8805/05A
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