NEC PD754244 Network Card User Manual


 
CHAPTER 6 PERIPHERAL HARDWARE FUNCTION
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User’s Manual U10676EJ3V0UM
6.4.4 Operation in 16-bit timer counter mode
In this mode, two timer counter channels, 1 and 2, are used in combination to implement 16-bit programmable
interval timer or event timer operation.
(1) Register setting
In the 16-bit timer counter mode, the following seven registers are used.
Timer counter mode registers TM1 and TM2
Timer counter control register TC2
Note
Timer count registers T1 and T2
Timer count modulo registers TMOD1 and TMO2
Note Timer counter channel 1 uses the timer counter output enable flag (TOE1).
(a) Timer counter mode registers (TM1 and TM2)
In the 16-bit timer counter mode, TM1 and TM2 are set as shown in Figure 6-40 (for the formats of TM1
and TM2, refer to Figure 6-27 Format of Timer Counter Mode Register (Channel 1) and Figure 6-
28 Format of Timer Counter Mode Register (Channel 2)).
TM1 and TM2 are manipulated by an 8-bit manipulation instruction. Bit 3 of these registers is a timer start
command bit that can be manipulated in 1-bit units and is automatically cleared to 0 when the timer starts
operating.
TM1 and TM2 are cleared to 00H when the internal reset signal is asserted.
The flags shown by a solid line in Figure 6-39 are used in the 16-bit timer counter mode.
Do not use the flags shown by a dotted line in the 16-bit timer counter mode (clear these flags to 0).