SAB82538 Datasheet, PDF (122/253 Pages) Infineon Technologies AG – ICs for Communications

Timer Register (READ/WRITE)
7
TIMR
CNT
VALUE
SAB 82538
SAF 82538
HDLC Mode
0
(offset: 23)
VALUE…
(5 bits) 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…
(3 bits) Interpreted differently depending 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 ESCC8 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 determine 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 is periodically generated after the
expiration of t₁.
Transmit Address Byte 1 (READ/WRITE)
7
2-byte address
XAD1
XAD1 (high byte)
1-byte address
XAD1
XAD1 (COMMAND)
0
0
(0) (offset: 24)
XAD1 (and XAD2) can be programmed with one individual address byte which is
appended automatically to the frame by ESCC8 in auto-mode. The function depends on
the selected address mode (bit ADM in MODE).
Semiconductor Group
122