ATSAM3S4AA-MU Atmel, ATSAM3S4AA-MU Datasheet - Page 370

• Manufacturer Part Number: ATSAM3S4AA-MU
• Description: IC MCU 32BIT 256KB FLASH 48QFN
• Manufacturer: Atmel
• Series: SAM3Sr

Specifications of ATSAM3S4AA-MU

• Core Processor: ARM® Cortex-M3™
• Core Size: 32-Bit
• Speed: 64MHz
• Connectivity: I²C, MMC, SPI, SSC, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, DMA, I²S, POR, PWM, WDT
• Number Of I /o: 34
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: FLASH
• Ram Size: 48K x 8
• Voltage - Supply (vcc/vdd): 1.62 V ~ 1.95 V
• Data Converters: A/D 8x10/12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-VQFN Exposed Pad, 48-HVQFN, 48-SQFN, 48-DHVQFN
• Processor Series: ATSAM3x
• Core: ARM Cortex M3
• 3rd Party Development Tools: JTRACE-CM3, MDK-ARM, RL-ARM, ULINK2
• Development Tools By Supplier: ATSAM3S-EK
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

23.8.1.5
23.8.2
23.8.2.1
23.8.2.2
370
SAM3S Preliminary
Read Mode
Null Pulse
Read is Controlled by NRD (READ_MODE = 1):
Read is Controlled by NCS (READ_MODE = 0)
Programming null pulse is not permitted. Pulse must be at least set to 1. A null value leads to
unpredictable behavior.
As NCS and NRD waveforms are defined independently of one other, the SMC needs to know
when the read data is available on the data bus. The SMC does not compare NCS and NRD tim-
ings to know which signal rises first. The READ_MODE parameter in the SMC_MODE register
of the corresponding chip select indicates which signal of NRD and NCS controls the read
operation.
Figure 23-7
data is available t
In this case, the READ_MODE must be set to 1 (read is controlled by NRD), to indicate that data
is available with the rising edge of NRD. The SMC samples the read data internally on the rising
edge of Master Clock that generates the rising edge of NRD, whatever the programmed wave-
form of NCS may be.
Figure 23-7. READ_MODE = 1: Data is sampled by SMC before the rising edge of NRD
Figure 23-8
falling edge of the NCS signal and remains valid until the rising edge of NCS. Data must be sam-
pled when NCS is raised. In that case, the READ_MODE must be set to 0 (read is controlled by
NCS): the SMC internally samples the data on the rising edge of Master Clock that generates
the rising edge of NCS, whatever the programmed waveform of NRD may be.
A[23:0]
D[7:0]
MCK
NRD
NCS
shows the waveforms of a read operation of a typical asynchronous RAM. The read
shows the typical read cycle of an LCD module. The read data is valid t
PACC
after the falling edge of NRD, and turns to ‘Z’ after the rising edge of NRD.
t
PACC
Data Sampling
6500C–ATARM–8-Feb-11
PACC
after the