SAM4S16C Atmel Corporation, SAM4S16C Datasheet - Page 684

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SAM4S16C

Manufacturer Part Number
SAM4S16C
Description
Manufacturer
Atmel Corporation
Datasheets

Specifications of SAM4S16C

Flash (kbytes)
1024 Kbytes
Pin Count
100
# Of Touch Channels
32
Hardware Qtouch Acquisition
No
Max I/o Pins
79
Ext Interrupts
79
Usb Transceiver
1
Quadrature Decoder Channels
2
Usb Speed
Full Speed
Usb Interface
Device
Spi
3
Twi (i2c)
2
Uart
4
Ssc
1
Sd / Emmc
1
Graphic Lcd
No
Video Decoder
No
Camera Interface
No
Adc Channels
16
Adc Resolution (bits)
12
Adc Speed (ksps)
1000
Analog Comparators
1
Resistive Touch Screen
No
Dac Channels
2
Dac Resolution (bits)
12
Temp. Sensor
Yes
Crypto Engine
No
Sram (kbytes)
128
Self Program Memory
YES
External Bus Interface
1
Dram Memory
No
Nand Interface
Yes
Picopower
No
Temp. Range (deg C)
-40 to 85
I/o Supply Class
1.8/3.3
Operating Voltage (vcc)
1.62 to 3.6
Fpu
No
Mpu / Mmu
Yes / No
Timers
6
Output Compare Channels
6
Input Capture Channels
6
Pwm Channels
4
32khz Rtc
Yes
Calibrated Rc Oscillator
Yes
31.7.3.4
684
684
SAM4S
SAM4S
Manchester Decoder
When the MAN field in US_MR register is set to 1, the Manchester decoder is enabled. The
decoder performs both preamble and start frame delimiter detection. One input line is dedicated
to Manchester encoded input data.
An optional preamble sequence can be defined, its length is user-defined and totally indepen-
dent of the emitter side. Use RX_PL in US_MAN register to configure the length of the preamble
sequence. If the length is set to 0, no preamble is detected and the function is disabled. In addi-
tion, the polarity of the input stream is programmable with RX_MPOL field in US_MAN register.
Depending on the desired application the preamble pattern matching is to be defined via the
RX_PP field in US_MAN. See
Unlike preamble, the start frame delimiter is shared between Manchester Encoder and Decoder.
So, if ONEBIT field is set to 1, only a zero encoded Manchester can be detected as a valid start
frame delimiter. If ONEBIT is set to 0, only a sync pattern is detected as a valid start frame
delimiter. Decoder operates by detecting transition on incoming stream. If RXD is sampled dur-
ing one quarter of a bit time to zero, a start bit is detected. See
rejection mechanism applies.
Figure 31-14. Asynchronous Start Bit Detection
The receiver is activated and starts Preamble and Frame Delimiter detection, sampling the data
at one quarter and then three quarters. If a valid preamble pattern or start frame delimiter is
detected, the receiver continues decoding with the same synchronization. If the stream does not
match a valid pattern or a valid start frame delimiter, the receiver re-synchronizes on the next
valid edge.The minimum time threshold to estimate the bit value is three quarters of a bit time.
If a valid preamble (if used) followed with a valid start frame delimiter is detected, the incoming
stream is decoded into NRZ data and passed to USART for processing.
Manchester pattern mismatch. When incoming data stream is passed to the USART, the
receiver is also able to detect Manchester code violation. A code violation is a lack of transition
in the middle of a bit cell. In this case, MANE flag in US_CSR register is raised. It is cleared by
writing the Control Register (US_CR) with the RSTSTA bit to 1. See
ple of Manchester error detection during data phase.
Manchester
Sampling
encoded
(16 x)
Clock
data
Txd
1
2
Figure 31-9
3
4
Detection
Start
for available preamble patterns.
Figure
Figure 31-16
31-14. The sample pulse
Figure 31-15
11100A–ATARM–28-Oct-11
11100A–ATARM–28-Oct-11
for an exam-
illustrates

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