Cirrus Logic EP93xx - Manual (Page 13)

DS785UM1
©
Copyright 2007 Cirrus Logic, Inc. xiii
EP93xx User’s Guide
23.5 Configuring the SSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23-2
23.5.1 Enabling SSP Operation..............................................................................................23-2
23.5.2 Master/Slave Mode......................................................................................................23-3
23.5.3 Serial Bit Rate Generation...........................................................................................23-3
23.5.4 Frame Format.............................................................................................................23-3
23.5.5 Texas Instruments
® Synchronous Serial Frame Format .............................................23-4
23.5.6 Motorola
®
SPI Frame Format ......................................................................................23-5
23.5.6.1 SPO Clock Polarity ....................................................................................23-5
23.5.6.2 SPH Clock Phase ......................................................................................23-5
23.5.7 Motorola SPI Format with SPO=0, SPH=0..................................................................23-5
23.5.8 Motorola SPI Format with SPO=0, SPH=1.................................................................23-7
23.5.9 Motorola SPI Format with SPO=1, SPH=0..................................................................23-8
23.5.10 Motorola SPI Format with SPO=1, SPH=1................................................................23-9
23.5.11 National Semiconductor
® Microwire ™ Frame Format .............................................23-10
23.5.11.1 Setup and Hold Time Requirements on SFRMIN with
Respect to SCLKIN in Microwire Mode ..................................................................23-12
23.6 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23-13
Chapter 24. Pulse Width Modulator ................................................................... 24-1
24.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24-1
24.2 Theory of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24-1
24.2.1 PWM Programming Examples ....................................................................................24-2
24.2.1.1 Example .....................................................................................................24-2
24.2.1.2 Static Programming (PWM is Not Running) Example ...............................24-2
24.2.1.3 Dynamic Programming (PWM is Running) Example .................................24-3
24.2.2 Programming Rules.....................................................................................................24-3
24.3 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24-3
Chapter 25. Analog Touch Screen Interface ..................................................... 25-1
25.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25-1
25.2 Touch Screen Controller Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25-1
25.2.1 Touch Screen Scanning: Four-wire and Eight-wire Operation ....................................25-4
25.2.2 Five-wire and Seven-wire Operation .........................................................................25-10
25.2.3 Direct Operation ........................................................................................................25-12
25.2.4 Measuring Analog Input with the Touch Screen Controls Disabled ..........................25-13
25.2.5 Measuring Touch Screen Resistance........................................................................25-15
25.2.6 Polled and Interrupt-Driven Modes............................................................................25-16
25.2.7 Touch Screen Package Dependency ........................................................................25-16
25.3 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25-17
Chapter 26. Keypad Interface ............................................................................. 26-1
26.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26-1
26.2 Theory of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26-2
26.2.1 Apparent Key Detection...............................................................................................26-3
26.2.2 Scan and Debounce ....................................................................................................26-5
26.2.3 Interrupt Generation ....................................................................................................26-5
26.2.4 Low Power Mode.........................................................................................................26-6
26.2.5 Three-key Reset ..........................................................................................................26-6
26.3 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26-6