Advance Information MC68HC908MR16/MC68HC908MR32 — Rev. 4.0
240 Timer Interface B (TIMB) MOTOROLA
Timer Interface B (TIMB)
12.8.2 TIMB Counter Registers
The two read-only TIMB counter registers contain the high and lo w bytes
of the value in the TIMB counter. Reading the high byte (TBCNTH)
latches the contents of the low byte (TBCNTL) into a buff er. Subsequent
reads of TBCNTH do not affect the latched TBCNTL value until TBCNTL
is read. Reset clears the TIMB counter registers. Setting the TIMB r eset
bit (TRST) also clears the TIMB counter registers.
NOTE: If TBCNTH is read during a break interrupt, be sure to unlatch TBCN TL
by reading TBCNTL before exiting the break interrupt. Otherwise,
TBCNTL retains the value latched during the break.
Register Name and Address: TBCNTH — $0052
Bit 7654321Bit 0
Read: Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:RRRRRRRR
Reset:00000000
Register Name and Address: TBCNTL — $0053
Bit 7654321Bit 0
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:RRRRRRRR
Reset:00000000
R = Reserved
Figure 12-5. TIMB Counter Registers (TBCNTH and TBCNTL)