upd78f0103hmca1-5a4-a Renesas Electronics Corporation., upd78f0103hmca1-5a4-a Datasheet - Page 153

• Manufacturer Part Number: upd78f0103hmca1-5a4-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(2) Operation with CR50 changed
7.5 Cautions for 8-Bit Timer/Event Counter 50
(1) Timer start error
Count clock
Count clock
INTTM50
Caution When reading from CR50 between <1> and <2> in Figure 7-11, the value read differs from the
An error of up to one clock may occur in the time required for a match signal to be generated after timer start.
This is because 8-bit timer counter 50 (TM50) is started asynchronously to the count clock.
INTTM50
TCE50
TM50
CR50
TO50
TCE50
TM50
CR50
TO50
H
actual value (read value: M, actual value of CR50: N).
N N + 1 N + 2
H
t
<1> CR50 change (N → M)
N N + 1 N + 2
t
N
(a) CR50 value is changed from N to M before clock rising edge of FFH
TM50 count value
(b) CR50 value is changed from N to M after clock rising edge of FFH
<1> CR50 change (N → M)
N
→ Value is transferred to CR50 at second overflow.
Count clock
→ Value is transferred to CR50 at overflow immediately after change.
Figure 7-11. Timing of Operation with CR50 Changed
Figure 7-12. 8-Bit Timer Counter 50 Start Timing
FFH 00H 01H
CHAPTER 7 8-BIT TIMER/EVENT COUNTER 50
FFH 00H 01H
<2>
00H
Timer start
02H
N
User’s Manual U16846EJ3V0UD
02H
M
N N + 1 N + 2
01H
M M + 1 M + 2
02H
FFH 00H 01H 02H
FFH 00H 01H 02H
<2>
03H
M
04H
M M+1 M+2
M M + 1 M + 2
153