668-0011 Rabbit Semiconductor, 668-0011 Datasheet - Page 35

• Manufacturer Part Number: 668-0011
• Description: IC MPU RABIT3000A 55.5MHZ128LQFP
• Manufacturer: Rabbit Semiconductor

Specifications of 668-0011

• Rohs Status: RoHS non-compliant
• Processor Type: Rabbit 3000 8-Bit
• Speed: 55.5MHz
• Voltage: 2.5V, 2.7V, 3V, 3.3V
• Mounting Type: Surface Mount
• Package / Case: 128-LQFP
• Features: -
• Other names: 316-1043

3.3 Operation
Pulling the /RESET pin low will initialize everything in the Rabbit 3000 except for the
real-time clock registers. The reset of the Rabbit 3000 is delayed until the completion of
any write cycles in progress; reset takes effect immediately when no write cycles are
occurring. The reset sequence requires a minimum of 128 cycles of the main clock to com-
plete in either case.
During reset, the impedance of the /CS1 pin is high and all other memory and I/O control
signals are held high. The special behavior of /CS1 allows an external RAM to be powered
by the same source as the VBATIO pin (which powers /CS1). In this case, a pullup resistor
is required on /CS1 to keep the RAM deselected during powerdown. The RESOUT pin is
high during reset and powerdown, but low at all other times, and can be used to control an
external power switch to disconnect VDDIO from VBATIO when the main power source
is removed.
Table 3-1 lists the condition of the processor after reset takes place. The state of all regis-
ters after reset is provided in the chapter describing the specific peripheral.
Chapter 3 Reset and Bootstrap
Memory Advanced
PC, SP, IIR, EIR,
Peripheral Clock
Interrupt Priority
Control Register
Control Register
Watchdog Timer
Watchdog Timer
Memory Bank 0
CPU Registers:
Clock Doubler
(IP Register)
CPU Clock,
Function
Secondary
SU, HTR
Table 3-1. Rabbit 3000 Condition After Reset
/CS0, /OE0, write-protected,
Operation After Reset
Enabled (2 seconds)
Divide-by-8 mode
0xFF (Priority 3)
8-bit interface
4 wait states
Disabled
Disabled
0x0000
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