Rainbow Electronics AT89C5122 - Manual (Page 54)

54
AT8xC5122/23
4202E–SCR–06/06
Port 1 Port 1 has the following functions:
– Default function : Only Port 1.2, P1.6 and P1.7 are standard I/O’s; the other
ports can be activated only with the SCIB function.
– Alternate function and configuration: see Table 31.
Table 31. Port 1 Description.
Port 2 Port 2 has the following functions:
– Default function: Port 2 is an 8-bit I/O port.
– Alternate function 1: Port 2 is also the multiplexed high-order address during
accesses to external Program and Data Memory. In this application, it uses
strong internal pull-ups when emitting 1’s and it can drive CMOS inputs
without external pull-ups.
Port 2 has the following configurations:
– Default configuration: Pseudo bi-directional “Port51” digital input/output with
internal pull-ups.
– Configuration 1: Push-pull output
– Configuration 2: Low speed output, “KB_OUT
– Configuration 3: Input with weak pull-up, “WPU input”
Port
Alternate Function Configuration
Signal Description Mode Comments
CIO
Smart card interface function
Card I/O
Quasi-bidirectional port supplied by
DC/DC converter
Low level at reset.
Caution : if DPU bit is set in AUXR register, the
weak-pull of the port is disabled
CC8
Smart card interface function
Card contact 8
Quasi-bidirectional port supplied by
DC/DC converter
Low level at reset
Caution : if DPU bit is set in AUXR register, the
weak-pull of the port is disabled
P1.2 CPRES
Smart card interface function
Card presence
Quasi-bidirectional port supplied by VCC
Weak & medium pull-up’s can be disconnected
by CPRESRES bit in PMOD0 regsiter
High Level at reset
CC4
Smart card interface function
Card contact 4
Quasi-bidirectional port supplied by
DC/DC converter
Low level at reset
Caution : if DPU bit is set in AUXR register, the
weak-pull of the port is disabled
CCLK
Smart card interface function
Card clock
Push-Pull port supplied by DC/DC
converter
Low level at reset
CRST
Smart card interface function
Card reset
Push-Pull port supplied by DC/DC
converter
Low level at reset
P1.6 SS SS pin of the SPI function Quasi-bidirectional supplied by VCC
P1.7 CCLK1 Alternate Card Clock output
Quasi-bidirectional supplied by VCC Alternate Card Clock function disabled
Quasi-bidirectional supplied by VCC
Alternate Smart Card Clock enabled
Switched automatically to Push-pull (see Table
47 on page 82 )