SAB 82525
SAB 82526
SAF 82525
SAF 82526
Timer Register (READ/WRITE)
75
40
TIMR
CNT
VALUE
(23/63)
VALUE … Sets the time period t1 as follows:
t1 = k × (VALUE + 1) ×TCP
where
–
k is the timer resolution factor which is either 32.768 or 512-clock cycles dependent on
the programming of TRS bit in MODE.
TCP is the clock period of transmit data.
–
CNT … Interpreted differently dependent on the selected timer mode (bit TMD in MODE).
Internal timer mode (MODE.TMD = 1)
retry counter (in HDLC known as N2)
CNT indicates the number of S-commands (max. 6) which are transmitted autonomously by
the HSCX after expiration of time period t1, in case an I-frame is not acknowledged by the
opposite station.
If CNT is set to 7, the number of S-commands is unlimited.
External timer mode (MODE,TMD = 0)
CNT plus VALUE indicates the time period t2 after which a timer interrupt will be
generated. The time period t2 is
t2 = 32 × k × CNT × TCP + t1
If CNT is set to 7, a timer interrupt periodically generated after the expiration of t1.
Semiconductor Group
91
SIEMENS [ Siemens Semiconductor Group ]
