Revision 1.1

Jun. 7, 1999

-14-

GL640USB, GL640USB-A

PCHBU

F2

PCHBU

F1

PCHBU

F0

Write buffer for upper 3-bit of Program Counter. The upper byte of Program Counter is not

directly accessible. PCHBUF is a holding register for the PC[10:8] whose contents are transferred

to the upper byte of the Program Counter.

Value on POR: “- - - - - 0 0 0”

INTEN (Address 0Bh/8Bh, Interrupt enable register)

R/W

R/W

R/W

GIE

TMROE

N

TMROF

GIE: Global interrupt enable bit

1: Enable all interrupts

0: Disable all interrupts

TMROEN: Timer overflow interrupt enable bit

1: Enable timer interrupt

0: Disable timer interrupt

TMROF: Timer overflow interrupt flag bit

1: Timer register has overflowed

0: Timer register did not overflow

Value on POR: “0 - 0 - - 0 - -“

PSCON (Address 81h, Prescaler control register)

R/W

R/W

R/W

R/W

PSDIS

PS2

PS1

PS0

PSEN: Prescaler disable bit

1: Disable prescaler for timer

0: Enable prescaler for timer

PS[2:0]: Prescaler rate select bits

Bit Value

Timer Rate

000

1:2

001

1:4