uPD780065 Subseries PUM - Renesas Electronics

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CHAPTER 13 SERIAL INTERFACE (UART0)
The transmit/receive clock that is used to generate the baud rate is obtained by dividing the main system
clock.
• Transmit/receive clock generation for baud rate by using main system clock
The main system clock is divided to generate the transmit/receive clock. The baud rate generated from
the main system clock is determined according to the following formula.
[Baud rate] =
fX
2 n+1 (k + 16)
[Hz]
fX: Main system clock oscillation frequency
n: Value set via TPS00 to TPS02 (0 ≤ n ≤ 7)
For details, see Table 13-2.
k: Value set via MDL00 to MDL03 (0 ≤ k ≤ 14)
Table 13-2 shows the relationship between the 5-bit counter’s source clock assigned to bits 4 to 6 (TPS00
to TPS02) of BRGC0 and the “n” value in the above formula.
Table 13-2. Relationship between 5-Bit Counter’s Source Clock and “n” Value
TPS02 TPS01 TPS00 5-Bit Counter’s Source Clock Selected n
0 0 0 P71/ASCK0 0
0 0 1 fX/2 1
0 1 0 fX/2 2 2
0 1 1 fX/2 3 3
1 0 0 fX/2 4 4
1 0 1 fX/2 5 5
1 1 0 fX/2 6 6
1 1 1 fX/2 7 7
Remark fX: Main system clock oscillation frequency
Preliminary User’s Manual U13420EJ2V0UM00