UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 469

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(2) Serial clock generation in 3-wire serial I/O mode
Selected when the CSCK1 bit of the clocked serial interface mode register (CSIM1) is set (1) and SCK1 is output.
(a) Normal mode
(b) High-speed mode
f
n
When this function is used, a number of baud rates can be generated by one external input clock.
The internal clock (f
the signal further divided by 2 is used as the serial clock. The serial clock is given by the following expression:
f
k : Value set in bits MDL3 to MDL0 of BRGC (k = 0 to 14)
n : Value set in bits TPS3 to TPS0 of BRGC (n = 0 to 11)
When this function is used, bits MDL3 to MDL0 of the baud rate generator control register (BRGC) are all set (1)
(k= 15).
The internal clock (f
clock. The serial clock is given by the following expression:
f
n : Value set in bits TPS3 to TPS0 of BRGC (n = 1 to 11)
ASCK
XX
XX
: Oscillator frequency or external clock input
: Oscillator frequency or external clock input
: ASCK pin input clock frequency
: Value set in bits TPS3 to TPS0 of BRGC (n = 0 to 11)
CHAPTER 16 ASYNCHRONOUS SERIAL INTERFACE/3-WIRE SERIAL I/O
XX
XX
/2) is scaled by the frequency divider, and this signal (f
/2) is scaled by the frequency divider, this signal (f
(Serial clock) =
(Serial clock) =
(Baud rate) =
(
k
f
2
ASCK
16 2
2
n
f
f
n
XX
XX
)
6
3
n
3
PRS
PRS
) is scaled by the 5-bit counter, and
) divided by 2 is used as the serial
429