SAM4S16C Atmel Corporation, SAM4S16C Datasheet - Page 54

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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
11.4.1.16
Name:
Access:
Reset:
The CONTROL register controls the stack used and the privilege level for software execution when the processor is in
Thread mode.
• SPSEL: Active Stack Pointer
Defines the current stack:
0: MSP is the current stack pointer.
1: PSP is the current stack pointer.
In Handler mode, this bit reads as zero and ignores writes. The Cortex-M4 updates this bit automatically on exception
return.
• nPRIV: Thread Mode Privilege Level
Defines the Thread mode privilege level:
0: privileged.
1: unprivileged.
Handler mode always uses the MSP, so the processor ignores explicit writes to the active stack pointer bit of the CON-
TROL register when in Handler mode. The exception entry and return mechanisms update the CONTROL register based
on the EXC_RETURN value.
In an OS environment, ARM recommends that threads running in Thread mode use the process stack, and the kernel and
exception handlers use the main stack.
By default, the Thread mode uses the MSP. To switch the stack pointer used in Thread mode to the PSP, either:
Note:
54
54
• use the MSR instruction to set the Active stack pointer bit to 1, see
• perform an exception return to Thread mode with the appropriate EXC_RETURN value, see
31
23
15
7
When changing the stack pointer, the software must use an ISB instruction immediately after the MSR instruction. This ensures
that instructions after the ISB execute using the new stack pointer. See
SAM4S
SAM4S
CONTROL Register
CONTROL
Read-write
0x00000000
30
22
14
6
0
29
21
13
5
28
20
12
4
27
19
11
3
“MSR”
“ISB”
, or
.
26
18
10
2
Table
SPSEL
25
17
9
1
11-10.
11100A–ATARM–28-Oct-11
11100A–ATARM–28-Oct-11
nPRIV
24
16
8
0

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