AT91SAM7S256C-MU Atmel, AT91SAM7S256C-MU Datasheet - Page 14

• Manufacturer Part Number: AT91SAM7S256C-MU
• Description: IC ARM7 MCU 32BIT 256K 64-QFN
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91SAM7S256C-MU

• Core Processor: ARM7
• Core Size: 16/32-Bit
• Speed: 55MHz
• Connectivity: I²C, SPI, SSC, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, DMA, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: FLASH
• Ram Size: 64K x 8
• Voltage - Supply (vcc/vdd): 1.65 V ~ 1.95 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-VQFN Exposed Pad, 64-HVQFN, 64-SQFN, 64-DHVQFN
• Processor Series: AT91
• Core: ARM7TDMI
• Data Bus Width: 32 bit
• Data Ram Size: 64 KB
• Interface Type: SPI, TWI, USART, USB
• Maximum Clock Frequency: 55 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 5
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• For Use With: AT91SAM-ICE - EMULATOR FOR AT91 ARM7/ARM9AT91SAM7S-EK - KIT EVAL FOR ARM AT91SAM7S
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details
• Other names: AT91SAM7S256-MU; AT91SAM7S256-MU

6. I/O Lines Considerations
6.1
6.2
6.3
6.4
6.5
14
JTAG Port Pins
Test Pin
Reset Pin
ERASE Pin
PIO Controller A Lines
AT91SAM7S Series Preliminary
TMS, TDI and TCK are schmitt trigger inputs. TMS and TCK are 5-V tolerant, TDI is not. TMS,
TDI and TCK do not integrate a pull-up resistor.
TDO is an output, driven at up to VDDIO, and has no pull-up resistor.
The JTAGSEL pin is used to select the JTAG boundary scan when asserted at a high level. The
JTAGSEL pin integrates a permanent pull-down resistor of about 15 kΩ to GND, so that it can be
left unconnected for normal operations.
The TST pin is used for manufacturing test, fast programming mode or SAM-BA Boot Recovery
of the AT91SAM7S Series when asserted high. The TST pin integrates a permanent pull-down
resistor of about 15 kΩ to GND, so that it can be left unconnected for normal operations.
To enter fast programming mode, the TST pin and the PA0 and PA1 pins should be tied high
and PA2 tied to low.
To enter SAM-BA Boot Recovery, the TST pin and the PA0, PA1 and PA2 pins should be tied
high for at least 10 seconds. Then a power cycle of the board is mandatory.
Driving the TST pin at a high level while PA0 or PA1 is driven at 0 leads to unpredictable results.
The NRST pin is bidirectional with an open drain output buffer. It is handled by the on-chip reset
controller and can be driven low to provide a reset signal to the external components or asserted
low externally to reset the microcontroller. There is no constraint on the length of the reset pulse,
and the reset controller can guarantee a minimum pulse length. This allows connection of a sim-
ple push-button on the pin NRST as system user reset, and the use of the signal NRST to reset
all the components of the system.
The NRST pin integrates a permanent pull-up resistor to VDDIO.
The ERASE pin is used to re-initialize the Flash content and some of its NVM bits. It integrates a
permanent pull-down resistor of about 15 kΩ to GND, so that it can be left unconnected for nor-
mal operations.
Programming of this pull-up resistor is performed independently for each I/O line through the
PIO controllers.
5V-tolerant means that the I/O lines can drive voltage level according to VDDIO, but can be
driven with a voltage of up to 5.5V. However, driving an I/O line with a voltage over VDDIO while
the programmable pull-up resistor is enabled will create a current path through the pull-up resis-
• All the I/O lines PA0 to PA31on AT91SAM7S512/256/128/64/321 (PA0 to PA20 on
• All the I/O lines PA0 to PA31 on AT91SAM7S161 (PA0 to PA20 on AT91SAM7S16) are not
AT91SAM7S32) are 5V-tolerant and all integrate a programmable pull-up resistor.
5V-tolerant and all integrate a programmable pull-up resistor.
6175K–ATARM–30-Aug-10