ez80f91 ZiLOG Semiconductor, ez80f91 Datasheet - Page 133

• Manufacturer Part Number: ez80f91
• Description: Ez80 Acclaimplus!? Connectivity Assp Ez80f91 Assp
• Manufacturer: ZiLOG Semiconductor

eZ80F91 ASSP
Product Specification
125
And when the end-of-count value (
) is reached, the EOC bit is set to 1 and an inter-
0000h
rupt service request signal is passed to the CPU. The interrupt service request signal is
deactivated by a CPU read of the timer interrupt identification register, TMRx_IIR.
All bits in that register are reset by the Read.
The response of the CPU to this interrupt service request is a function of the CPU’s inter-
®
rupt enable flag, IEF1. For more information about this flag, refer to the eZ80
CPU User
Manual (UM0077) available on www.zilog.com.
Timer Input Source Selection
Timers 0–3 features programmable input source selection. By default, the input is taken
from the eZ80F91’s system clock. The timers also use the Real-Time Clock source (50,
60, or 32768 Hz) as their clock sources. The input source for these timers is set using the
timer control register. (TMRx_CTL[CLK_SEL])
Timer Output
The timer count is directed to the GPIO output pins, if required. To enable the Timer
Output feature, the GPIO port pin must be configured as an output and for alternate func-
tions. The GPIO output pin toggles each time the timer reaches its end-of-count value.
In CONTINUOUS mode operation, enabling the Timer Output feature results in a Timer
Output signal period which is twice the timer time-out period. Examples of Timer Output
operation are illustrated in
Figure 29
and
Table 52
on page 126. The initial value for the
timer output is zero.
Logic to support timer output exists in all timers; but for the eZ80F91 device, only Timer
0 and 2 route the actual timer output to the pins. Because Timer 3 uses the T
pins for
OUT
PWMxN signals, the timer outputs are not available when using complementary PWM
outputs. See
Table 52
on page 126 for details.
PS027001-0707
Programmable Reload Timers