M55800A Atmel Corporation, M55800A Datasheet - Page 102
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M55800A
Manufacturer Part Number
M55800A
Description
Manufacturer
Atmel Corporation
Datasheets
1.M40800.pdf
(284 pages)
2.M40800.pdf
(153 pages)
3.M55800A.pdf
(29 pages)
4.M55800A.pdf
(256 pages)
5.M55800A.pdf
(28 pages)
Specifications of M55800A
Flash (kbytes)
0 Kbytes
Pin Count
176
Max. Operating Frequency
33 MHz
Cpu
ARM7TDMI
Hardware Qtouch Acquisition
No
Max I/o Pins
58
Ext Interrupts
58
Usb Speed
No
Usb Interface
No
Spi
1
Uart
3
Graphic Lcd
No
Video Decoder
No
Camera Interface
No
Adc Channels
8
Adc Resolution (bits)
10
Adc Speed (ksps)
72
Resistive Touch Screen
No
Dac Channels
1
Dac Resolution (bits)
10
Temp. Sensor
No
Crypto Engine
No
Sram (kbytes)
8
Self Program Memory
NO
External Bus Interface
1
Dram Memory
No
Nand Interface
No
Picopower
No
Temp. Range (deg C)
-40 to 85
I/o Supply Class
3.3/5.0
Fpu
No
Mpu / Mmu
no / no
Timers
6
Output Compare Channels
6
Input Capture Channels
6
32khz Rtc
Yes
Calibrated Rc Oscillator
No
Synchronous Receiver
Receiver Ready
Parity Error
Framing Error
Time-out
102
AT91X40 Series
When configured for synchronous operation (SYNC = 1), the receiver samples the RXD
signal on each rising edge of the Baud Rate clock. If a low level is detected, it is consid-
ered as a start. Data bits, parity bit and stop bit are sampled and the receiver waits for
the next start bit. See example in Figure 40.
Figure 40. Synchronous Mode: Character Reception
When a complete character is received, it is transferred to the US_RHR and the RXRDY
status bit in US_CSR is set. If US_RHR has not been read since the last transfer, the
OVRE status bit in US_CSR is set.
Each time a character is received, the receiver calculates the parity of the received data
bits, in accordance with the field PAR in US_MR. It then compares the result with the
received parity bit. If different, the parity error bit PARE in US_CSR is set.
If a character is received with a stop bit at low level and with at least one data bit at high
level, a framing error is generated. This sets FRAME in US_CSR.
This function allows an idle condition on the RXD line to be detected. The maximum
delay for which the USART should wait for a new character to arrive while the RXD line
is inactive (high level) is programmed in US_RTOR (Receiver Time-out). When this reg-
ister is set to 0, no time-out is detected. Otherwise, the receiver waits for a first character
and then initializes a counter which is decremented at each bit period and reloaded at
each byte reception. When the counter reaches 0, the TIMEOUT bit in US_CSR is set.
The user can restart the wait for a first character with the STTTO (Start Time-out) bit in
US_CR.
Calculation of time-out duration:
Example: 8-bit, parity enabled 1 stop
Sampling
SCK
RXD
True Start Detection
D0
Duration
D1
= Value x
D2
D3
4
D4
x
Bit period
D5
D6
D7
1354D–ATARM–08/02
Parity Bit
Stop Bit