Epson S1C17624 Technical Manual page 115

10 Fine Mode 8-bit Timers (T8F)
10.1 T8F Module Overview
The S1C17624/604/622/602/621 includes two-channel fine mode 8-bit timer module (T8F).
The features of the T8F module are listed below.
• 8-bit presettable down counter with an 8-bit reload data register for setting the preset value
• Generates the UART operating clock from the counter underflow signals.
• Generates underflow interrupt signals to the interrupt controller (ITC).
• Any desired time intervals and serial transfer rates can be programmed by selecting an appropriate count clock
and preset value.
• Fine mode is provided to minimize transfer rate errors.
Figure 10.1.1 shows the T8F configuration.
PCLK
CLG
To ITC
To UART Ch.0 (from Ch.0)
To UART Ch.1 (from Ch.1)
Each channel of the T8F module consists of an 8-bit presettable down counter and an 8-bit reload data register
holding the preset value. The timer counts down from the initial value set in the reload data register and outputs an
underflow signal when the counter underflows. The underflow signal is used to generate an interrupt and an internal
serial interface clock. The underflow cycle can be programmed by selecting the count clock and reload data, en-
abling the application program to obtain time intervals and serial transfer rates as required.
note: Both T8F channels have the same functions except for the control register addresses. The de-
scription in this chapter applies to both channels. The 'x' in the register name refers to the channel
number (0 or 1).
Example: T8F_CTLx register
Ch.0: T8F_CTL0 register
Ch.1: T8F_CTL1 register
S1C17624/604/622/602/621 TeChniCal Manual
TRMD
Count mode select
TFMD[3:0]
Fine mode setting
DF[3:0]
Count clock select
Divider
(1/1–1/16K)
Interrupt request
Clock outputs
Figure 10. 1.1 T8F Configuration (1 Channel)
Seiko epson Corporation
10 Fine MODe 8-BiT TiMeRS (T8F)
8-bit timer Ch.x
PRESER
Timer reset
PRUN
Run/stop control
Control Reload data register
circuit T8F_TRx
Down counter
T8F_TCx
Fine mode
Underflow
10-1