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CONTENTS
12.6.1.4 Using Mixed Analog and Digital Inputs ............................................................12-13
12.6.2 Understanding A/D Conversion Errors ..................................................................12-13
CHAPTER 13
MINIMUM HARDWARE CONSIDERATIONS
13.1 MINIMUM CONNECTIONS ......................................................................................... 13-1
13.1.1 Unused Inputs .........................................................................................................13-2
13.1.2 I/O Port Pin Connections ........................................................................................13-2
13.2 APPLYING AND REMOVING POWER....................................................................... 13-4
13.3 NOISE PROTECTION TIPS ........................................................................................ 13-4
13.4 THE ON-CHIP OSCILLATOR CIRCUITRY ................................................................. 13-5
13.5 USING AN EXTERNAL CLOCK SOURCE.................................................................. 13-7
13.6 RESETTING THE DEVICE.......................................................................................... 13-8
13.6.1 Generating an External Reset ...............................................................................13-10
13.6.2 Issuing the Reset (RST) Instruction ......................................................................13-12
13.6.3 Issuing an Illegal IDLPD Key Operand .................................................................13-12
13.6.4 Generating Wait States .........................................................................................13-12
13.6.5 Enabling the Watchdog Timer ...............................................................................13-12
CHAPTER 14
SPECIAL OPERATING MODES
14.1 SPECIAL OPERATING MODE SIGNALS AND REGISTERS..................................... 14-1
14.2 REDUCING POWER CONSUMPTION ....................................................................... 14-3
14.3 IDLE MODE ................................................................................................................. 14-4
14.4 POWERDOWN MODE ................................................................................................ 14-5
14.4.1 Enabling and Disabling Powerdown Mode ..............................................................14-5
14.4.2 Entering Powerdown Mode .....................................................................................14-6
14.4.3 Exiting Powerdown Mode .......................................................................................14-6
14.4.3.1 Driving the V
pp
Pin Low ......................................................................................14-6
14.4.3.2 Generating a Hardware Reset ...........................................................................14-6
14.4.3.3 Asserting the External Interrupt Signal ...............................................................14-7
14.4.3.4 Selecting R
1
and C
1
...........................................................................................14-8
14.5 ONCE MODE............................................................................................................. 14-10
14.6 RESERVED TEST MODES....................................................................................... 14-11
CHAPTER 15
INTERFACING WITH EXTERNAL MEMORY
15.1 EXTERNAL MEMORY INTERFACE SIGNALS AND REGISTERS ............................ 15-1
15.2 CHIP CONFIGURATION REGISTERS AND CHIP CONFIGURATION BYTES ......... 15-5
15.3 BUS WIDTH AND MULTIPLEXING........................................................................... 15-10
15.3.1 Timing Requirements for BUSWIDTH ...................................................................15-13
15.3.2 16-bit Bus Timings ................................................................................................15-14
15.3.3 8-bit Bus Timings ..................................................................................................15-16