CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U14492EJ3V0UD
475
(2) Dedicated baud rate generators 1, 2 (BRG1, BRG2)
BRGn is configured of an 8-bit timer counter for baud rate signal generation, a prescaler mode register that
controls the generation of the baud rate signal (PRSMn), a prescaler compare register that sets the value of
the 8-bit timer counter (PRSCMn), and a prescaler (n = 1, 2).
(a) Input clock
The internal system clock (f
XX
) is input to BRGn.
(b) Prescaler mode registers 1, 2 (PRSM1, PRSM2)
The PRSMn register controls generation of the UARTn baud rate signal (n = 1, 2).
These registers can be read/written in 8-bit or 1-bit units.
Cautions 1. Do not change the values of the BGCS1 and BGCS0 bits during transmission/
reception operations.
2. Set PRSMn register other than the UARTCEn bit prior to setting the UARTCEn bit to
1 (n = 1, 2).
<7>
UARTCE1
PRSM1
6
0
5
0
4
0
3
0
2
0
1
BGCS1
0
BGCS0
Address
FFFFFA2EH
Initial value
00H
<7>
UARTCE2
PRSM2
6
0
5
0
4
0
3
0
2
0
1
BGCS1
0
BGCS0
Address
FFFFFA4EH
Initial value
00H
Bit Position
Bit Name
Function
7
UARTCEn
Enables baud rate counter operation.
0: Stop baud rate counter operation and fix baud rate output signal to “0”.
1: Enable baud rate counter operation and start baud rate output operation.
Selects count clock to baud rate counter.
BGCS1
BGCS0
Count Clock Selection
0
0
f
XX
/2
0
1
f
XX
/4
1
0
f
XX
/8
1
1
f
XX
/16
1, 0
BGCS1,
BGCS0
Remark
f
XX
: Internal system clock
Remark
n = 1, 2
Содержание V850E/IA1 mPD703116
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