Rainbow Electronics T89C5121 - Manual (Page 52)

52
A/T8xC5121
4164G–SCR–07/06
Table 35. ISEL Register
Reset Value = 0000 0100b
7 6 5 4 3 2 1 0
CPLEV OEIT PRESIT RXIT OELEV OEEN PRESEN RXEN
Bit
Number
Bit
Mnemonic Description
7 CPLEV
Card presence detection level
This bit indicates which CPRES level will bring about an interrupt
Set this bit to indicate that Card Presence IT will appear if CPRES is at high
level.
Clear this bit to indicate that Card Presence IT will appear if CPRES is at low
level.
6 -
Reserved
The value read from this bit is indeterminate. Do not set this bit.
5 PRESIT
Card presence detection interrupt flag
Set by hardware
Must be cleared by software
4 RXIT
Received data interrupt flag
Set by hardware
Must be cleared by software
3 OELEV
OE/INT1 signal active level
Set this bit to indicate that high level is active.
Clear this bit to indicate that low level is active.
2 OEEN
OE/INT1 Interrupt Disable bit
Clear to disable INT1 interrupt
Set to enable INT1 interrupt
1 PRESEN
Card presence detection Interrupt Enable bit
Clear to disable the card presence detection interrupt coming from SCIB.
Set to enable the card presence detection interrupt coming from SCIB.
0 RXEN
Received data Interrupt Enable bit
Clear to disable the RxD interrupt.
Set to enable the RxD interrupt (a minimal bit width of 0.1 ms is required to
wake up from Power-Down).