at94k40al ATMEL Corporation, at94k40al Datasheet - Page 80

• Manufacturer Part Number: at94k40al
• Description: At94kal Series Field Programmable System Level Integrated Circuit
• Manufacturer: ATMEL Corporation

4.22.2.2
4.22.2.3
4.22.2.4
4.22.2.5
4.22.3
4.22.3.1
80
AT94KAL Series FPSLIC
Boundary-scan Chain
IDCODE; $1
SAMPLE_PRELOAD; $2
AVR_RESET; $C
BYPASS; $F
Scanning the Digital Port Pins
Optional JTAG instruction selecting the 32-bit ID register as Data Register. The ID register con-
sists of a version number, a device number and the manufacturer code chosen by JEDEC. This
is the default instruction after power-up.
The active states are:
Mandatory JTAG instruction for pre-loading the output latches and taking a snap-shot of the
input/output pins without affecting the system operation. However, the output latches are not
connected to the pins. The Boundary-Scan Chain is selected as Data Register.
The active states are:
The AVR specific public JTAG instruction for forcing the AVR device into the Reset Mode or
releasing the JTAG reset source. The TAP controller is not reset by this instruction. The one bit
Reset Register is selected as Data Register. Note that the reset will be active as long as there is
a logic “1” in the Reset Chain. The output from this chain is not latched.
The active state is:
Mandatory JTAG instruction selecting the Bypass Register for Data Register.
The active states are:
The Boundary-Scan chain has the capability of driving and observing the logic levels on the
AVR’s digital I/O pins.
Figure 4-20
cell consists of a standard boundary-scan cell for the pull-up function, and a bi-directional pin
cell that combines the three signals Output Control (OC), Output Data (OD), and Input Data (ID),
into only a two-stage shift register.
• Capture-DR: Data on the external pins are sampled into the Boundary-Scan Chain.
• Shift-DR: The Internal Scan Chain is shifted by the TCK input.
• Update-DR: Data from the scan chain is applied to output pins.
• Capture-DR: Data in the IDCODE register is sampled into the Boundary-Scan Chain.
• Shift-DR: The IDCODE scan chain is shifted by the TCK input.
• Capture-DR: Data on the external pins are sampled into the Boundary-Scan Chain.
• Shift-DR: The Boundary-Scan Chain is shifted by the TCK input.
• Update-DR: Data from the Boundary-Scan chain is applied to the output latches. However,
• Shift-DR: The Reset Register is shifted by the TCK input.
• Capture-DR: Loads a logic “0” into the Bypass Register.
• Shift-DR: The Bypass Register cell between TDI and TDO is shifted.
the output latches are not connected to the pins.
shows the boundary-scan cell for bi-directional port pins with pull-up function. The
1138I–FPSLI–1/08