Oki MSM85C154HVS User Manual

INTERNAL SPECIFICATIONS
93
EXF2 : Timer/counter 2 external flag bit which is set when the T2EX pin level (bit 1 of
port 1) is changed from “1” to “0” at EXEN2=1. This flag serves as the timer
interrupt 2 request signal. When an interrupt is generated, this flag must be reset
to “0” by software.
TF2 : Timer/counter 2 internal flag bit which is set when a carry signal is generated by
timer/counter 2 in 16-bit auto reload mode or capture mode. This flag serves as
the timer interrupt 2 request signal. When an interrupt is generated, this flag
must be reset to “0” by software.
4.5.3.3 Timer/counter 2 operation modes
Timer/counter 2 operation modes are set by combinations of the CP/RL2, TCLK, and RCLK
bits in timer 2 control register (T2CON 0C8H) shown in Table 4-13. The timer modes are listed
in Table 4-14.
Table 4-13 Timer 2 control register (T2CON 0C8H)
Bit
Flag
Set
76543210
TF2 EXF2 RCLK TCLK EXEN2 TR2 C/T2 CP/RL2
•• •
Table 4-14 Timer/counter 2 modes
RCLK TCLK CP/ RL2 TR2
0001
0011
RCLK + TCLK = 1 × 1
×××0
Mode
16-bit auto reload
16-bit capture
Baud rate generator
All operations stopped
4.5.3.3.1 16-bit auto reload mode
16-bit auto reload mode is set by making the circuit connection shown in Figure 4-20 by setting
RCLK=0, TCLK=0, and CP/RL2=0 as the bit conditions in timer 2 control register (T2CON).
Timer/counter 2 operates in the following way when 16-bit auto reload mode is set. When a
timer/counter 2 carry signal is generated, or when the signal applied to the T2EX pin (bit 1
of port 1) is changed from level “1” to “0”, the reload data in the RCAP2L and RCAP2H
registers is preset in L2 and TH2 of timer/counter 2. The timer/counter thus starts counting
from this preset value.
The timer/counter 2 carry signal is set in internal timer flag 2 (TF2), and the T2EX change is
set in external timer flag 2 (EXF2). The TF2 and EXF2 serve as the timer interrupt 2 request
signals with an interrupt call being made to address 43 (2BH) if the timer interrupt 2 has been
enabled. If an interrupt routine is commenced, the TF2 and EXF2 flags must be reset to “0”
by software.

Oki MSM85C154HVS Specifications

General

Brand	Oki
Model	MSM85C154HVS
Category	Controller
Language	English