Rainbow Electronics T89C5121 - Manual (Page 36)

36
A/T8xC5121
4164G–SCR–07/06
Figure 22. Alternate Card
Card Presence Input The internal pull-up on Card Presence input can be disconnected in order to reduce the
consumption (CPRESRES, bit 3 in PMOD0).
In this case, an external resistor (typically 1 M
Ω
) must be externally tied to V
CC
.
CPRES input can generate an interrupt (see Interrupt system section).
The detection level can be selected.
SCIB Reset The SCICR register contains a reset bit. If set, this bit generates a reset of the SCI and
its registers. Table 15 shows the SCIB registers that are reseted and their reset values.
Table 14. Reset Values for SCI Registers
SIM,SAM
CARD
Alternate
card
C V
CC
CRST
CIO
CCLK
F
CK_IDLE 1
0
CCLK1
SCSR Reg.
PR3
SCSR Reg.
ALTKPS0,1 SCCLK1
F
CK_IDLE
1, 2, 4 or 8
P3.6
Main
card
CPRES
Register Name SCIB Reset Value (Binary)
SCICR 0000 0000b
SCCON 0X00 0000b
SCISR 1000 0000b
SCIIR 0X00 0000b
SCIER 0X00 0000b
SCSR XXX0 1000b
SCTBUF 0000 0000b
SCRBUF 0000 0000b
SCETU1, SCETU0 XXX X001b, 0111 0100b (372)
SCGT1, SCGT0 XXXX XXX0b, 0000 1100b (12)
SCWT2, SCWT1, SCWT0 0000 0000b, 0010 0101b, 1000 0000b (9600)