ATXMEGA256A3B-MH Atmel, ATXMEGA256A3B-MH Datasheet - Page 352

• Manufacturer Part Number: ATXMEGA256A3B-MH
• Description: MCU AVR 256KB FLASH A3B 64-QFN
• Manufacturer: Atmel
• Series: AVR® XMEGAr

Specifications of ATXMEGA256A3B-MH

• Core Processor: AVR
• Core Size: 8/16-Bit
• Speed: 32MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, DMA, POR, PWM, WDT
• Number Of I /o: 49
• Program Memory Size: 256KB (128K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 16K x 8
• Voltage - Supply (vcc/vdd): 1.6 V ~ 3.6 V
• Data Converters: A/D 16x12b; D/A 2x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-MLF®, 64-QFN
• Processor Series: ATXMEGA256x
• Core: AVR8
• Data Bus Width: 8 bit, 16 bit
• Data Ram Size: 16 KB
• Interface Type: I2C, SPI, USART
• Maximum Clock Frequency: 32 MHz
• Number Of Programmable I/os: 49
• Number Of Timers: 7
• Operating Supply Voltage: 1.6 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12 bit, 8 Channel
• On-chip Dac: 12 bit, 2 Channel
• For Use With: ATAVRONEKIT - KIT AVR/AVR32 DEBUGGER/PROGRMMRATSTK600 - DEV KIT FOR AVR/AVR32770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAG770-1004 - ISP 4PORT FOR ATMEL AVR MCU SPI
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ATXMEGA256A3B-MU; ATXMEGA256A3B-MU

29.4.6
29.4.6.1
8077H–AVR–12/09
Serial transmission
Status signalling
Figure 29-12. Changing and sampling data
When data transmission is initiated, a data byte is loaded in parallel into the shift register, and
then serialized by shifting the byte out on TDO. The Parity bit is generated and stitched to the
data byte during transmission. The transmission speed is dictated by the TCK signal.
If the PDI is in TX-mode (as a response to an LD-instruction), and a transmission request from
the PDI Controller is pending when the TAP-controller enters the Capture-DR state, valid data
will be parallel-loaded into the shift-register and a correct Parity bit will be generated and trans-
mitted along with the data byte in the Shift-DR state.
If the PDI is in RX-mode when the TAP-controller enters the Capture-DR state, an EMPTY byte
(0xEB) will be parallel-loaded into the shift-register, and the Parity bit will be set (forcing a parity
error) when data is shifted out in the Shift-DR state. This situation occurs during normal PDI
command - and operand reception.
If the PDI is in TX-mode (as a response to an LD-instruction), but no transmission request from
the PDI Controller is yet pending when the TAP-controller enters the Capture-DR state, a
DELAY byte (0xDB) will be parallel-loaded into the shift-register, and the Parity bit will be set
(forcing a parity error) when data is shifted out in the Shift-DR state. This situation occurs during
data transmission if the data to be transmitted is not yet available.
Figure 29-13 on page 352
a response to the repeated indirect LD instruction. However, in this example the device is not
able to return data bytes faster than one valid byte per two transmitted frames, intermediate
DELAY characters are inserted.
Figure 29-13. Date not ready marking
If a DELAY data frame is transmitted as a response to an LD instruction, the programmer should
interpret this as if the JTAG-interface had no data yet ready for transmission in the previous DR-
Capture state. The proper reaction from the programmer is to initiate repeated transfers until a
valid data byte is received. The LD-instruction is defined to return a specified number of valid
frames, not just a number of frames. Hence if the programmer detects a DELAY Character after
transmitting an LD-instruction, the LD-instruction should not be retransmitted, because the first
LD response would still be pending.
Programmer
External
Commands/data
TD I/TDO
TC K
Device
FRAME 0
shows an uninterrupted flow of data frames from the PDI (Device) as
REP
FRAME 1
CNT
S am ple
LD *(ptr)
FRAME 2
0xDB 1
S am ple
FRAME 0
FRAME 1
D0
P 0xDB 1
S am ple
FRAME 2
XMEGA A
FRAME 3
D1
P
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