6-4
Clock, Power Management, and Reset
The RESET_OUT_N signal is ANDed with the HRESET# output of the RISCWatch probe, allowing either
the CPC700 or the RISCWatch probe to reset the CPU. Since the CPC700 is not reset by a RISCWatch
HRESET#, there is no need to extend HRESET# to the CPU.
The RESET_OUT_N signal is also ANDed with the TRST# output of the RISCWatch probe. To assure cor-
rect operation, the JTAG facility must re reset whenever the processor core is reset by the system. In Fig-
ure 45, TRST# follows HRESET# in response to a board reset. Also, the RISCWatch probe is allowed to
reset the CPU core (via HRESET#) and the JTAG interface (via TRST#) separately. This capability is
required by the RISCWatch probe.
The SRESET# output of the RISCWatch probe drives the SRESET# input of the CPU. Additional
resources of SRESET# can be ANDed in.
6.3.1.1 Changes from Earlier Documentation
Some pre-release versions of the CPC700 documentation showed pin L17 as SRESET_N, and showed
this pin driving the SRESET# input of the CPU; however, the function of this pin is to hold the CPU in hard
reset, so the pin was renamed as RESET_OUT_N and is now one of the sources driving HRESET# to the
CPU.
6.3.2 Internal Peripheral Reset Control
In addition to being reset with the system reset (SYS_RESET_N), the individual internal peripherals may
each be reset by firmware through the Peripheral Reset Control register in the CPR. The reset to each of
the internal peripherals is controlled by setting the appropriate bit the in the Reset Control Register. The
reset will remain active until the bit is re-written back to a zero.The Peripheral Reset Control register is
described in Table 65.
6.4 Power on Reset Pin Strapping Options
During the period of time while the SYS_RESET_N input pin is low (system reset) the state of certain I/O
pins is read to enable default conditions of the CPC700 prior to boot. These pins may be strapped using
external pullup or pulldown resisters which will set different operating conditions. Table 62. and Table 63.
list the strapping pins along with their functions. External strapping resistors should be 3 Kohms or stron-
ger.
Table 62. General Strapping Options
CPC700 I/O
Function
Notes
TT[0]
TT[1]
TT[4]
TSIZ[0]
GBL_N
Boot ROM Bank
Width
8 - bit
pulldown
pulldown
16 - bit
pulldown
pullup
32 - bit
pullup
pulldown
64 - bit
pullup
pullup
Internal PCI Arbiter
/
Processor Data
Parity Select
Enable PCI Arbiter
pullup
Enable Processor
Data Parity
pulldown
Summary of Contents for CPC700
Page 10: ...Table of Contents x Table of Contents...
Page 16: ...Tables xvi List of Tables...
Page 28: ...1 12 CPC700 User s Manual Preliminary...
Page 72: ...3 36 Processor Interface...
Page 132: ...4 60 Memory Controller...
Page 184: ...5 52 PCI Interface...
Page 194: ...6 10 Clock Power Management and Reset...
Page 224: ...8 18 IIC...
Page 244: ...10 10 Interrupt Controller...
Page 246: ...I 11 2 JTAG...
Page 250: ...12 4 Processor Local Bus PLB...
Page 262: ...14 10 Register Summary...
Page 267: ...CPC700 User s Manual Preliminary...