NEC mPD789026 Subseries, User Manual

Page: 129 / 213

CHAPTER 9 SERIAL INTERFACE 00
User's Manual U11919EJ3V0UM00
129
(4) Baud rate generator control register 00 (BRGC00)
This register is used to set the serial clock of serial interface 00.
BRGC00 is set with an 8-bit memory manipulation instruction.
RESET input clears BRGC00 to 00H.
Figure 9-6. Baud Rate Generator Control Register 00 Format
TPS003
0
0
0
0
0
0
0
0
1
TPS003 TPS002 TPS001 TPS000 0 0 0 0 BRGC00
R/W
FF73H 00H R/W
7 6 5 4 3 2 1 0
TPS002
0
0
0
0
1
1
1
1
0
f
X
/2
f
X
/2
2
f
X
/2
3
f
X
/2
4
f
X
/2
5
f
X
/2
6
f
X
/2
7
f
X
/2
8
(2.5 MHz)
(1.25 MHz)
(625 kHz)
(313 kHz)
(156 kHz)
(78.1 kHz)
(39.1 kHz)
(19.5 kHz)
TPS001
0
0
1
1
0
0
1
1
0
TPS000
0
1
0
1
0
1
0
1
0
n
1
2
3
4
5
6
7
8
–
Setting prohibited
Symbol Address
After Reset
3-Bit Counter Source Clock Selection
Input clock from external to ASCK pin
Note
Other than above
Note Only used in UART mode.
Cautions 1. When writing to BRGC00 is performed during a communication operation, the baud
rate generator output is disrupted and communications cannot be performed normally.
Be sure not to write to BRGC00 during communication operation.
2. Be sure not to select n = 1 during an operation at f
X
= 5.0 MHz because n = 1 exceeds
the baud rate limit.
3. When selecting an input clock from an external source, set port mode register 2 (PM2)
to the input mode.
Remarks 1. f
X
: System clock oscillation frequency
2. n : Value determined by setting TPS000 through TPS003 (1
≤
n
≤
8)
3. The parenthesized values apply to operation at f
X
= 5.0 MHz.