- Am79C930 PCnetTM-Mobile Single-Chip Wireless LAN Media Access Controller

AMD
P R E L I M I N A R Y
56
Am79C930
The following is a brief summary of the IEEE 1149.1
compatible test functions implemented in the
Am79C930 device:
Boundary Scan Circuit
The boundary scan test circuit uses five pins: TRST,
TCK, TMS, TDI, and TDO. These five pins are collec-
tively labeled the TAP. The boundary scan test circuit in-
cludes a finite state machine (FSM), an instruction
register, and a data register array. Internal pull-up resis-
tors are provided for the TDI and TMS pins. The TCK pin
must not be left unconnected.
TAP FSM
The TAP engine is a 16-state FSM, driven by the Test
Clock (TCK) and the Test Mode Select (TMS) pins. This
FSM is in its reset state at power up or after H_RESET.
The TRST pin is supported in order to ensure that the
FSM is in the TEST_LOGIC_RESET state before test-
ing is begun.
Supported Instructions
In addition to the minimum IEEE 1149.1 requirements
(BYPASS, EXTEST, and SAMPLE instructions), one
additional instruction (IDCODE) is provided as addi-
tional support for board level testing.
All unused instruc-
tion decodes are reserved.
Instruction Name Instruction Code Mode Selected Data Register Description
EXTEST 0000 Test BSR External Test
ID_CODE 0001 Normal ID REG ID Code Inspection
SAMPLE 0010 Normal BSR Sample Boundary
Reserved 0011–1110 Reserved Reserved Reserved
BYPASS 1111 Normal Bypass Bypass Scan
Instruction Register and Decoding Logic
After H_RESET or S_RESET, the IDCODE instruction
is always loaded into the IEEE 1149.1 register. The de-
coding logic gives signals to control the data flow in the
DATA registers according to the current instruction.
Boundary Scan Register (BSR)
Each BSR cell has two stages. A flip-flop and a latch
are used for the SERIAL SHIFT STAGE and for the
PARALLEL OUTPUT STAGE, respectively.
There are four possible operation modes in the
BSR cell:
1 Capture
2 Shift
3 Update
4 System Function
Other Data Registers
(1) BYPASS REGISTER (1 BIT)
(2) DEVICE ID REGISTER (32 BITS)
(3) INSCAN0
Device ID Register Contents:
Bits 31–28: Version
Bits 27–12: Part Number (0010 1000 0101 0000)
Bits 11–1: Manufacturer ID. The 11 bit manufacturer
ID code for AMD is 00000000001 in accor-
dance with JEDEC publication 106-A.
Bit 0: Always a logic 1
This is an internal scan path for AMD internal
testing use.
Power Saving Modes
Power Down Function
The Am79C930 BIU includes five registers that are used
to invoke a power-down function that will support the
IEEE 802.11 (draft) specified power down by allowing
variable lengths of power-down and power-up time. The
registers include the Processor Interface Register
(MIR0), which contains the Power Down command bit, a
Power Down Length Count set of registers (MIR2,3,4),
and a Power Up Clock Timer (MIR1) register. The power
down sequence is executed by the firmware running
on the embedded 80188, either independently, or in
response to a request from the host. In the PCMCIA