69rlq62d-f714peg4 * Memec (Headquar
ter
s) - Unique
Tec
h,
Insight,
Impact
MAR
VELL CONFIDENTIAL,
UNDER ND
A# 12101050
69rlq62d-f714peg4 * Memec (Headquar
ter
s) - Unique
Tec
h,
Insight,
Impact
MAR
VELL CONFIDENTIAL,
UNDER ND
A# 12101050
69r
lq62d-f714peg4 * Memec (Headquar
ters) - Unique
T
ech, Insight, Impact * UNDER ND
A# 12101050
MAR
VELL CONFIDENTIAL - UNA
UTHORIZED DISTRIB
UTION OR USE STRICTL
Y PR
OHIBITED
JTAG
Copyright © 12/13/06 Marvell
CONFIDENTIAL
Doc. No. MV-TBD-00 Rev. A
December 13, 2006
Document Classification: Proprietary Information
Page 451
Not approved by Document Control. For review only.
JTAG
17
17.1
Overview
This chapter describes all supported JTAG features for the PXA300 processor or PXA310 processor. JTAG
provides a way of driving and sampling the external pins of the device regardless of the core state. This enables
test of both the device electrical connections to the circuit board and (in conjunction with other devices on the
circuit board having a similar interface) the integrity of the circuit board connections between devices. JTAG
also provides a mechanism for device debug via the Intel XScale
®
CPU debug features.
JTAG logic includes a test-access port (TAP) controller, TAP pins, an instruction register, and test data registers
(TDRs). These TDRs include the Boundary Scan register (BSR - the register used to directly control the IO pins),
Bypass register, Device Identification (ID) register, and data-specific registers, as shown in
. Data are
shifted into all registers most significant bit (MSB) first serially. The JTAG interface is controlled through five
dedicated TAP controller pins that interface to the TAP controller: TDI, TMS, TCK, nTRST, and TDO.
17.1.1
Differences Between PXA300 Processor and PXA310
Processor
The JTAG device IDs are different for the PXA300 processor and PXA310 processor (see
Device Identification Register
). However, there are no differences between the JTAG logic of the PXA300
processor or PXA310 processor.
Figure 17-1. JTAG Block Diagram
Instruction
TAP
Controller
Boundary Scan Register
Device ID Register
Bypass Register
Data Specific Registers
Register
TDI
TMS
TCK
nTRST
Control and Clock Signals
TDO