EP7209 Datasheet, PDF (48/128 Pages) Cirrus Logic – Ultra-Low-Power Audio Decoder System-on-Chip

EP7209
default on test-logic reset and any of the system re-
sets.
The contents of the device ID-register for the
EP7209 are shown in Table 23. This is equivalent
to 0x0F0F0F0F. Note this is the ID-code for the
ARM720T processor.
3.18 In-Circuit Emulation
3.18.1 Introduction
EmbeddedICE is an extension to the architecture of
the ARM family of processors, and provides the
ability to debug cores that are deeply embedded
into systems. It consists of three parts:
1) A set of extensions to the ARM core
2) The EmbeddedICE macrocell, to provide ac-
cess the extensions from the outside world
3) The EmbeddedICE interface to provide com-
munication from the EmbeddedICE macrocell
and the host computer
The EmbeddedICE macrocell is programmed, in a
serial fashion, through the TAP controller on the
ARM via the JTAG interface. The EmbeddedICE
macrocell is by default disabled to minimize power
usage, and must be enabled at boot-up to support
this functionality.
3.18.2 Functionality
The ICEBreaker module consists of two real-time
watchpoint units together with a control and status
register. One or both of the units can be pro-
grammed to halt the execution of the instructions
by the ARM processor. Execution is halted when
either a match occurs between the values pro-
grammed into the ICEBreaker and the values cur-
rently appearing on the address bus, data bus, and
the various control signals. Any bit can be masked
to remove it from the comparison. Either unit can
be programmed as a watchpoint (monitoring data
accesses) or a breakpoint (monitoring instruction
fetches).
Using one of these watchpoint units, an unlimited
number of software breakpoints (in RAM) can be
supported by substitution of the actual code.
NOTE:
The EXTERN[1:0] signals from the ICE-
Breaker module are not wired out in this
device. This mechanism is used to allow
watchpoints to be dependent on an external
event. This behavior can be emulated in
software via the ICEBreaker control regis-
ters.
A more detailed description is available in the
ARM Software Development Toolkit User Guide
and Reference Manual. The ICEBreaker module
and its registers are fully described in the
ARM7TDMI Data Sheet.
3.19 Maximum EP7209-Based System
A maximum configured system using the EP7209
is shown in Figure 12. This system assumes the
ROMs are 16-bit wide devices. The keyboard may
be connected to more GPIO bits than shown to al-
low greater than 64 keys, however these extra pins
will not be wired into the WAKEUP pin function-
ality.
Version
Part number
Manufacturer ID
00001111000011110000111100001111
Table 23. Device ID Register
48
DS453PP2