SAK-C505L Infineon Technologies AG, SAK-C505L Datasheet - Page 30

• Manufacturer Part Number: SAK-C505L
• Description: 8-bit CMOS Microcontroller
• Manufacturer: Infineon Technologies AG

Digital I/O Ports
The C505L has five 8-bit and one 6-bit (port 5) digital I/O ports. Port 0 is an open-drain bidirectional
I/O port, while ports 1 through 5 are quasi-bidirectional I/O ports with internal pull-up resistors.
When configured as inputs, ports 1-5 will be pulled high, and will source current when externally
pulled low. Port 0 will float when configured as input.
The output drivers of port 0 and 2 and the input buffers of port 0 are also used for accessing external
memory. In this application, port 0 outputs the low byte of the external memory address, time-
multiplexed with the byte being written or read. Port 2 outputs the high byte of the external memory
address when the address is 16 bits wide. Otherwise, the port 2 pins continue emitting the P2
Special Function register (SFR) contents. In this function, port 0 is not an open-drain port, but uses
a strong internal pull-up.
Therefore, the parallel I/O ports of the C505L can be grouped into six different types which are listed
in Table 5.
Table 5
C505L Port Structure Types
Type
A
B
C
D
E
F
Type A and B port pins are standard C501-compatible I/O port lines, which can be used for digital
I/O. The type A ports (port 0 and port 2) are also designed for accessing external data or program
memory. Type B port lines are located at port 3 (except P3.4 and P3.5), and are used for digital I/
O or for other alternate functions as described in the pin description. Type D port lines provide the
LCD controller outputs R0-R3 and C0-C15 as primary functions. Type E port lines are located at
port 4 and port 5 and provide the LCD controller output lines as alternate functions. Type F port lines
are at P3.4/T0 and P3.5/T1 and have a digital alternate input each, apart from LCD output functions.
The C505L provides eight analog input lines that are implemented as mixed digital/analog inputs
(type C). The 8 analog inputs, AN0-AN7, are located at the port 1 pins P1.0 to P1.7. After reset, all
analog inputs are disabled and the related pins of port 1 are configured as digital inputs. The analog
function of the specific port 1 pins are enabled by bits in the SFRs P1ANA. Writing a 0 to a bit
position of P1ANA assigns the corresponding pin to operate as analog input.
Note: P1ANA is a mapped SFR and can only be accessed if bit RMAP in SFR SYSCON is set.
lf a digital value is to be read by port 1, the voltage levels are to be held within the input voltage
specifications (
Data Sheet
Description
Standard digital I/O ports which can also be used for external address/data bus.
Standard multifunctional digital I/O port lines
Mixed digital/analog I/O port lines with programmable analog input function
LCD Output Lines
Standard digital I/O or LCD output lines
Standard multifunctional digital I/O or LCD output lines
V
IL
/
V
IH
).
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C505L
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