Digi NS9750 User Manual

Page 326

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S y s t e m c o n f i g u r a t i o n r e g i s t e r s

3 0 2

N S 9 7 5 0 H a r d w a r e R e f e r e n c e

Register bit assignment

Bits

Access

Mnemonic

Reset

Description

31:16

N/A

Reserved

N/A

N/A

D15

R/W

TEN

0x0

Timer enable

0

Timer is disabled

1

Timer is enabled

D14:10

N/A

Reserved

N/A

N/A

D09

R/W

INTC

0x0

Interrupt clear

Clears the timer interrupt. System software must write a 1,
then a 0 to this location to clear the interrupt.

If the timer is programmed to halt on terminal count (that
is, REN is clear), the software must disable the timer by
setting TEN to 0 before clearing the interrupt by writing a
1 and then a 0 to INTC.

D08:06

R/W

TLCS

0x0

Timer clock select

000

CPU clock (must be used if this is the high word
of two concatenated timers)

001

CPU clock / 2

010

CPU clock / 4

011

CPU clock / 8

100

CPU clock / 16

101

CPU clock / 32

110

CPU clock / 64

111

External pulse event

Notes:

Counting external pulse events, the frequency must

be less than one-half the CPU clock frequency.

For TLCS settings 000 – 110, the terminal count can

be output using GPIO. The terminal count pulse
width will be one CPU clock cycle, regardless of the
TLCS setting.

Table 190: Timer Control register

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