Specifications

Zylogic ZE5 Configurable System-on-Chip Platform
www.Zylogic.com.cn 46
mechanism (J_INTR). For additional details, refer
to the “Reset Conditions” section.
The JTAG unit serves as a bus slave when inter-
acting with the DMA controller. It first becomes
master on the CSI bus, programs the DMA unit to
transfer data to or from the JTAG unit, and then
relinquishes the CSI bus to the DMA controller.
After configuring the DMA, the JTAG unit inter-
faces with the DMA controller as a slave device
using the DMA's request and acknowledge signals.
There is considerably less overhead in this type of
data transactions since the JTAG unit does not
need to provide address or control information dur-
ing DMA operations.
Serving as a bus master, the JTAG unit is able to
set breakpoint events within the breakpoint unit,
which is also a slave connected on the CSI bus.
The breakpoint unit supports two independent
breakpoint conditions. The breakpoint unit moni-
tors user-specified combinations of address, data,
control or DMA signals as breakpoint events. The
user can also count logic conditions occurring in-
side the CSL as breakpoint events. A breakpoint
specification can count up to 64K-1 incidents as
the matching condition for a break event.
Once a breakpoint condition occurs, then depend-
ing on its current configuration, the MCU freezes at
the end of the current instruction or receives a
breakpoint interrupt and branches to execute de-
bugger interrupt routines. Following a breakpoint
freeze, CSL clocks or global signals can be
blocked to aid system debugging. The Zylogic
FastChip software enables the user to specify
which CSL clocks or global signals are affected
following a breakpoint freeze.
During a CPU freeze period, the JTAG unit can
poll any addressable location residing inside or
outside the CSoC and send all requested informa-
tion to the host PC for further display and analysis.
At the end of the debugging session, JTAG clears
the breakpoint “freeze MCU” condition and the
8032 “Turbo” microcontroller resumes code execu-
tion from where it left off. Alternatively, the JTAG
unit can restart code execution from 0000h by is-
suing a J_RESET command to the MCU.
At any point in time, the JTAG unit can instruct the
MCU to enter a single-step operation and send
pertinent display information to the host PC.