![background image](http://html2.mh-extra.com/html/rabbit/3000/3000_user-manual_3114034147.webp)
User’s Manual
139
11.2 Timer B
Figure 11-1 shows a block diagram of Timer B. The Timer B counter can be driven
directly by
perclk
/2, by that clock divided by 8, or by the output of Timer A1. Timer B
has a continuously running 10-bit counter. The counter is compared against two match
registers, the B1 match register and the B2 match register. When the counter transitions to
a value equal to a match register, an internal pulse with a length of 1 peripheral clock is
generated. The match pulse can be used to cause interrupts and/or clock the output regis-
ters of Parallel Ports D and E.
The match registers are loaded from the match preload registers that are written to by an
I/O instruction. The data byte in the match preload register is advanced to the next match
register when the match pulse is generated.
Every time a match condition occurs, the processor sets an internal bit that marks the match
value in TBLxR as invalid. Reading TBCSR clears the interrupt condition. TBLxR must be
reloaded to re-enable the interrupt. TBMxR does not need to be reloaded every time.
If both match registers need to be changed, the most significant byte needs to be changed first.
The I/O registers for Timer B are listed in Table 11-6.
Table 11-6. Timer B Registers
Register Name
Mnemonic
I/O
address
R/W
Reset
Timer B Control/Status Register
TBCSR
0xB0
R/W
xxxxx000
Timer B Control Register
TBCR
0xB1
W
xxxx0000
Timer B MSB 1 Register
TBM1R
0xB2
W
xxxxxxxx
Timer B LSB 1 Register
TBL1R
0xB3
W
xxxxxxxx
Timer B MSB 2 Register
TBM2R
0xB4
W
xxxxxxxx
Timer B LSB 2 Register
TBL2R
0xB5
W
xxxxxxxx
Timer B Count MSB Register
TBCMR
0xBE
R
xxxxxxxx
Timer B Count LSB Register
TBCLR
0xBF
R
xxxxxxxx
Содержание 3000
Страница 1: ...Rabbit 3000 Microprocessor User s Manual 019 0108 020426 A...
Страница 8: ...Rabbit 3000 Microprocessor...
Страница 28: ...20 Rabbit 3000 Microprocessor...
Страница 73: ...User s Manual 65 6 RABBIT INTERNAL I O REGISTERS...
Страница 122: ...114 Rabbit 3000 Microprocessor...
Страница 138: ...130 Rabbit 3000 Microprocessor...
Страница 150: ...142 Rabbit 3000 Microprocessor...
Страница 188: ...180 Rabbit 3000 Microprocessor...
Страница 208: ...200 Rabbit 3000 Microprocessor...
Страница 228: ...220 Rabbit 3000 Microprocessor...
Страница 232: ...224 Rabbit 3000 Microprocessor...
Страница 238: ...230 Rabbit 3000 Microprocessor...
Страница 260: ...252 Rabbit 3000 Microprocessor...
Страница 266: ......