CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U14492EJ3V0UD
443
(4) Allowable baud rate range during reception
The degree to which a discrepancy from the transmission destination’s baud rate is allowed during reception
is shown below.
Caution
The equations described below should be used to set the baud rate error during reception
so that it always is within the allowable error range.
Figure 10-13. Allowable Baud Rate Range During Reception
FL
1 data frame (11
×
FL)
FLmin
FLmax
UART0
transfer rate
Latch timing
Start bit
Bit 0
Bit 1
Bit 7
Parity bit
Minimum allowable
transfer rate
Maximum allowable
transfer rate
Stop bit
Start bit
Bit 0
Bit 1
Bit 7
Parity bit
Stop bit
Start bit
Bit 0
Bit 1
Bit 7
Parity bit
Stop bit
As shown in Figure 10-13, after the start bit is detected, the receive data latch timing is determined according
to the counter that was set by the BRGC0 register. If all data up to the final data (stop bit) is in time for this
latch timing, the data can be received normally.
Applying this to 11-bit reception is, theoretically, as follows.
FL = (Brate)
–1
Brate: UART0 baud rate
k:
BRGC0 register setting value
FL:
1-bit data length
When the latch timing margin is made 2 base clocks, the minimum allowable transfer rate (FLmin) is
as follows.
FL
k
2
2
k
21
FL
k
2
2
k
FL
11
min
FL
+
=
×
−
−
×
=
Содержание V850E/IA1 mPD703116
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