NEC - page 232

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CHAPTER 9 8-BIT TIMER/EVENT COUNTERS 1 AND 2
(3) Square-wave output operation
Operates as square wave output with any selected frequency at intervals of the count value preset to 8-bit
compare register 10 and 20 (CR10, CR20).
The TO1/P31 or TO2/P32 pin output status is reversed at intervals of the count value preset to CR10 or CR20
by setting bit 0 (TOE1) or bit 4 (TOE2) of the 8-bit timer output control register (TOC1) to 1. This enables
a square wave with any selected frequency to be output.
Table 9-8. 8-Bit Timer/Event Counters 1 and 2 Square-Wave Output Ranges
Minimum Pulse Width Maximum Pulse Width Resolution
MCS = 1 MCS = 0 MCS = 1 MCS = 0 MCS = 1 MCS = 0
2 × 1/fX22 × 1/fX29 × 1/fX210 × 1/fX2 × 1/fX22 × 1/fX
(400 ns) (800 ns) (102.4 µ s) (204.8 µ s) (400 ns) (800 ns)
22 × 1/fX23 × 1/fX210 × 1/fX211 × 1/fX22 × 1/fX23 × 1/fX
(800 ns) (1.6 µ s) (204.8 µ s) (409.6 µ s) (800 ns) (1.6 µ s)
23 × 1/fX24 × 1/fX211 × 1/fX212 × 1/fX23 × 1/fX24 × 1/fX
(1.6 µ s) (3.2 µ s) (409.6 µ s) (819.2 µ s) (1.6 µ s) (3.2 µ s)
24 × 1/fX25 × 1/fX212 × 1/fX213 × 1/fX24 × 1/fX25 × 1/fX
(3.2 µ s) (6.4 µ s) (819.2 µ s) (1.64 ms) (3.2 µ s) (6.4 µ s)
25 × 1/fX26 × 1/fX213 × 1/fX214 × 1/fX25 × 1/fX26 × 1/fX
(6.4 µ s) (12.8 µ s) (1.64 ms) (3.28 ms) (6.4 µ s) (12.8 µ s)
26 × 1/fX27 × 1/fX214 × 1/fX215 × 1/fX26 × 1/fX27 × 1/fX
(12.8 µ s) (25.6 µ s) (3.28 ms) (6.55 ms) (12.8 µ s) (25.6 µ s)
27 × 1/fX28 × 1/fX215 × 1/fX216 × 1/fX27 × 1/fX28 × 1/fX
(25.6 µ s) (51.2 µ s) (6.55 ms) (13.1 ms) (25.6 µ s) (51.2 µ s)
28 × 1/fX29 × 1/fX216 × 1/fX217 × 1/fX28 × 1/fX29 × 1/fX
(51.2 µ s) (102.4 µ s) (13.1 ms) (26.2 ms) (51.2 µ s) (102.4 µ s)
29 × 1/fX210 × 1/fX217 × 1/fX218 × 1/fX29 × 1/fX210 × 1/fX
(102.4 µ s) (204.8 µ s) (26.2 ms) (52.4 ms) (102.4 µ s) (204.8 µ s)
211 × 1/fX212 × 1/fX219 × 1/fX220 × 1/fX211 × 1/fX212 × 1/fX
(409.6 µ s) (819.2 µ s) (104.9 ms) (209.7 ms) (409.6 µ s) (819.2 µ s)
Remarks 1. fX: Main system clock oscillation frequency
2. MCS : Oscillation mode selection register (OSMS) bit 0
3. Values in parentheses when operated at fX = 5.0 MHz.