CHAPTER 11 SERIAL INTERFACE UART0 (
µ
PD78F0102H AND 78F0103H ONLY)
Preliminary User’s Manual U16846EJ1V0UD
210
Cautions 1. When the Ring-OSC clock is selected as the clock to be supplied to the CPU, the clock of the
Ring-OSC oscillator is divided and supplied as the count clock. If the base clock is the Ring-
OSC clock, the operation of serial interface UART0 is not guaranteed.
2. Make sure that bit 6 (TXE0) and bit 5 (RXE0) of the ASIM0 register = 0 when rewriting the
MDL04 to MDL00 bits.
3. The baud rate value is the output clock of the 5-bit counter divided by 2.
Remarks 1. f
XCLK0
: Frequency of base clock selected by the TPS01 and TPS00 bits
2. f
X
: High-speed system clock oscillation frequency
3. k: Value set by the MDL04 to MDL00 bits (k = 8, 9, 10, ..., 31)
4.
×
: Don’t
care
5. Figures in parentheses apply to operation at f
X
= 10 MHz
(4) Port mode register 1 (PM1)
This register sets port 1 input/output in 1-bit units.
When using the P10/TxD0/SCK10 pin for serial interface data output, clear PM10 to 0 and set the output latch of
P10 to 1.
Set PM11 to 1 when using the P11/RxD0/SI10 pin as a serial interface data input pin. The output latch of P11 at
this time may be 0 or 1.
PM1 can be set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets this register to FFH.
Figure 11-5. Format of Port Mode Register 1 (PM1)
Address: FF21H After reset: FFH R/W
Symbol
7 6 5 4 3 2 1 0
PM1
PM17 PM16 PM15 PM14 PM13 PM12 PM11 PM10
PM1n
P1n pin I/O mode selection (n = 0 to 7)
0
Output mode (output buffer on)
1
Input mode (output buffer off)