Semiconductor Group
6-1
1999-04-01
On-Chip Peripheral Components
C541U
6
On-Chip Peripheral Components
This chapter gives detailed information about all on-chip peripherals of the C541U except for the
integrated interrupt controller, which is described separately in chapter 7.
6.1
Parallel I/O
The C541U three 8-bit I/O ports and one 6-bit I/O port (Port 1). Port 0 is an open-drain bidirectional
I/O port, while ports 1 to 3 are quasi-bidirectional I/O ports with internal pullup resistors. That means,
when configured as inputs, ports 1 to 3 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 SFR
contents. In this function, port 0 is not an open-drain port, but uses a strong internal pullup FET.
Two port lines of port 1 (P1.0/LED0, P1.1/LED1) and one port line of port 3 (P3.0/LED2) have the
capability of driving external LEDs in the output low state.
Содержание C541U
Страница 1: ... 8 LW 026 0LFURFRQWUROOHU 8VHU V 0DQXDO http www siem ens d Sem iconductor ...
Страница 7: ......
Страница 21: ...Semiconductor Group 2 6 1997 10 01 Fundamental Structure C541U ...
Страница 37: ...Semiconductor Group 4 6 1997 10 01 External Bus Interface C541U ...
Страница 133: ...Semiconductor Group 6 88 1999 04 01 On Chip Peripheral Components C541U ...
Страница 163: ...Semiconductor Group 8 8 1997 10 01 Fail Safe Mechanisms C541U ...
Страница 185: ...Semiconductor Group 10 14 1997 10 01 OTP Memory Operation C541U ...
Страница 192: ...Semiconductor Group 12 7 Index C541U ...