 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
PIC12LF1571 Datasheet(PDF) 9 Page - Microchip Technology |
|
||||||||||||||||||||||||||||||
PIC12LF1571 Datasheet(HTML) 9 Page - Microchip Technology |
|
|
9 / 32 page  2013 Microchip Technology Inc. DS40001713A-page 9 PIC12(L)F1571/2 4.0 PROGRAM/VERIFY MODE In Program/Verify mode, the program memory and the configuration memory can be accessed and programmed in serial fashion. ICSPDAT and ICSPCLK are used for the data and the clock, respectively. All commands and data words are transmitted LSb first. Data changes on the rising edge of the ICSPCLK and is latched on the falling edge. In Program/Verify mode, both the ICSPDAT and ICSPCLK are Schmitt Trigger inputs. The sequence that enters the device into Program/Verify mode places all other logic into the Reset state. Upon entering Program/Verify mode, all I/Os are automatically configured as high-impedance inputs and the address is cleared. 4.1 High-Voltage Program/Verify Mode Entry and Exit There are two different methods of entering Program/ Verify mode via high voltage: •VPP – First entry mode •VDD – First entry mode 4.1.1 VPP – FIRST ENTRY MODE To enter Program/Verify mode via the VPP-first method, the following sequence must be followed: 1. Hold ICSPCLK and ICSPDAT low. All other pins should be unpowered. 2. Raise the voltage on MCLR from 0V to VIHH. 3. Raise the voltage on VDD from 0V to the desired operating voltage. The VPP-first entry prevents the device from executing code prior to entering Program/Verify mode. For example, when the Configuration Word has MCLR disabled (MCLRE = 0), the power-up time is disabled (PWRTE = 0), the internal oscillator is selected (FOSC = 100), and RA0 and RA1 are driven by the user application, the device will execute code. Since this may prevent entry, VPP-first entry mode is strongly recommended. See the timing diagram in Figure 8-2. 4.1.2 VDD – FIRST ENTRY MODE To enter Program/Verify mode via the VDD-first method, the following sequence must be followed: 1. Hold ICSPCLK and ICSPDAT low. 2. Raise the voltage on VDD from 0V to the desired operating voltage. 3. Raise the voltage on MCLR from VDD or below to VIHH. The VDD-first method is useful when programming the device when VDD is already applied, for it is not necessary to disconnect VDD to enter Program/Verify mode. See the timing diagram in Figure 8-1. 4.1.3 PROGRAM/VERIFY MODE EXIT To exit Program/Verify mode take MCLR to VDD or lower (VIL). See Figures 8-3 and 8-4. 4.2 Low-Voltage Programming (LVP) Mode The Low-Voltage Programming mode allows the devices to be programmed using VDD only, without high voltage. When the LVP bit of the Configuration Word 2 register is set to ‘1’, the low-voltage ICSP programming entry is enabled. To disable the Low-Voltage ICSP mode, the LVP bit must be programmed to ‘0’. This can only be done while in the High-Voltage Entry mode. Entry into the Low-Voltage ICSP Program/Verify mode requires the following steps: 1. MCLR is brought to VIL. 2. A 32-bit key sequence is presented on ICSPDAT, while clocking ICSPCLK. The key sequence is a specific 32-bit pattern, '0100 1101 0100 0011 0100 1000 0101 0000' (more easily remembered as MCHP in ASCII). The device will enter Program/Verify mode only if the sequence is valid. The Least Significant bit of the Least Significant nibble must be shifted in first. Once the key sequence is complete, MCLR must be held at VIL for as long as Program/Verify mode is to be maintained. For low-voltage programming timing, see Figures 8-8 and 8-9. Exiting Program/Verify mode is done by no longer driving MCLR to VIL. See Figures 8-8 and 8-9. Note: To enter LVP mode, the LSb of the Least Significant nibble must be shifted in first. This differs from entering the key sequence on other parts. |
Similar Part No. - PIC12LF1571 |
|
Similar Description - PIC12LF1571 |
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.COM |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
