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E Text Script for eLearning course "Resets" Table of contents Topic Slide Number Introduction 1 Reset Mechanisms 2 Reset Status bits 3 Power-on Reset 4 Brown-out Reset 5 Knowledge Check #1 6 MCLR Pin 7 Driving MCLR 8 MCLR Effects 9 Watch-dog Timer 10 Knowledge Check #2 11 Closing 12 Text Script for "Resets" Page 1 of 10 *h Slide 1: Introduction Microchip Technology welcomes you to the Reset module of the PICmicro x14 microcontroller. This module will give you a basic overview of the PICmicro MCU Resets and is intended for those new to PICmicro MCU or requiring a refresher on Resets. It is recommended you have previously taken or are familiar with the PIC MCU x14 architecture and instruction set modules. Slide 2: Reset Mechanisms There are four kinds of reset mechanisms fo r the PIC MCU x14 architecture. The first two have to do with resetting the part based on power to the device. They are Power-On Reset, which occurs on start-up, and Brown-Out Reset, which holds the part in reset if the Vdd value drops below a safe level. You can also force a reset by using the MCLR pin and lastly, the internal Watchdog Timer can cause a reset if it is allowed to time out. This presentation will discuss each of these reset mechanisms in detail. Text Script for "Resets" Page 2 of 10 *h Slide 3: Reset Status Bits Before we discuss the details of each reset mechanism, we should point out some status bits that are important for this discussion. Availability of these bits is product dependent, so please look at the datasheet for the product you are planning on using. There are 2 bits in the status register and 2 bits in the Power Control and Status (PCON) register that can be used to determine what event caused a reset condition. In the Status register, we are interested in the Time-out (TO) bit and the Power- down (PD) bit. The Time-out (TO) bit is set to a 1 after power-up, a CLRWDT instruction or a Sleep instruction. The TO bit is only cleared to a 0 when a WDT timeout has occurred. The Power-down (PD) bit is set high after a power-up or the execution of the CLRWDT instruction. This bit will be cleared low only by the execution of the sleep instruction. In the Power Control (PCON) register, we use the Power-on Res