SAM4S16C Atmel Corporation, SAM4S16C Datasheet - Page 785

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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
33.5.3
33.5.3.1
33.5.3.2
33.5.3.3
11100A–ATARM–28-Oct-11
11100A–ATARM–28-Oct-11
Transmitter
Transmitter Reset, Enable and Disable
Transmit Format
Transmitter Control
After device reset, the UART transmitter is disabled and it must be enabled before being used.
The transmitter is enabled by writing the control register UART_CR with the bit TXEN at 1. From
this command, the transmitter waits for a character to be written in the Transmit Holding Register
(UART_THR) before actually starting the transmission.
The programmer can disable the transmitter by writing UART_CR with the bit TXDIS at 1. If the
transmitter is not operating, it is immediately stopped. However, if a character is being pro-
cessed into the Shift Register and/or a character has been written in the Transmit Holding
Register, the characters are completed before the transmitter is actually stopped.
The programmer can also put the transmitter in its reset state by writing the UART_CR with the
bit RSTTX at 1. This immediately stops the transmitter, whether or not it is processing
characters.
The UART transmitter drives the pin UTXD at the baud rate clock speed. The line is driven
depending on the format defined in the Mode Register and the data stored in the Shift Register.
One start bit at level 0, then the 8 data bits, from the lowest to the highest bit, one optional parity
bit and one stop bit at 1 are consecutively shifted out as shown in the following figure. The field
PARE in the mode register UART_MR defines whether or not a parity bit is shifted out. When a
parity bit is enabled, it can be selected between an odd parity, an even parity, or a fixed space or
mark bit.
Figure 33-9. Character Transmission
When the transmitter is enabled, the bit TXRDY (Transmitter Ready) is set in the status register
UART_SR. The transmission starts when the programmer writes in the Transmit Holding Regis-
ter (UART_THR), and after the written character is transferred from UART_THR to the Shift
Register. The TXRDY bit remains high until a second character is written in UART_THR. As
soon as the first character is completed, the last character written in UART_THR is transferred
into the shift register and TXRDY rises again, showing that the holding register is empty.
When both the Shift Register and UART_THR are empty, i.e., all the characters written in
UART_THR have been processed, the TXEMPTY bit rises after the last stop bit has been
completed.
Baud Rate
Example: Parity enabled
UTXD
Clock
Start
Bit
D0
D1
D2
D3
D4
D5
D6
D7
Parity
Bit
SAM4S
SAM4S
Stop
Bit
785
785

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