at75c220 ATMEL Corporation, at75c220 Datasheet - Page 74

• Manufacturer Part Number: at75c220
• Description: Smart Internet Appliance Processor Siap
• Manufacturer: ATMEL Corporation

USART: Universal Synchronous/Asynchronous Receiver/Transmitter
The AT75C220 provides two identical full-duplex, universal
synchronous/asynchronous receiver/transmitters as
USART A and USART B. These peripherals sit on the APB
bus but are also connected to the ASB bus (and hence
external memory) via a dedicated DMA.
The main features are:
• Programmable baud rate generator
• Parity, framing and overrun error detection
Figure 15. USART Block Diagram
Pin Description
Each USART channel has external signals as defined in Table 22.
Table 22. USART External Signals
74
Signal Name
SCK
TXD
RXD
USxIRQ
ACLK/8
ACLK
ASB
APB
AMBA
Description
USART Serial Clock. Can be configured as input or output. See US_MR
Transmit Serial Data
Receive Serial Data
AT75C220
Peripheral Data Controller
Baud Rate Generator
Receive
Channel
Modem Control
Interrupt Control
Control Logic
Transmit
Channel
Baud Rate Clock
• Line break generation and detection
• Automatic echo, local loopback and remote loopback
• Multi-drop mode: address detection and generation
• Interrupt generation
• Two dedicated peripheral data controller channels
• 6-, 7- and 8-bit character length
• Modem control signals
USART Channel
channel modes
Transmitter
Receiver
PIO A
Output
RXD
TXD
SCK
Type
NRTS
NCTS
NRI
NDTR
NDSR
NDCD
Input
I/O