Lỗi Debug ICD2. Connect OK, Read OK, Program failed

[dang tuan]

chào các ban.

mình đã kiểm tra lại thấy: khi lấy nguồn từ ICD2 thì ok,
còn khi lấy nguồn từ mạch (target) thì nó báo:
Connecting to MPLAB ICD 2
...Connected
Setting Vdd source to target
Target Device PIC16F877A found, revision = Rev 0x8
...Reading ICD Product ID
Running ICD Self Test
... Failed Self Test. See ICD2 Settings (Programmer->Settings) (status tab) for details.
MPLAB ICD 2 ready for next operation
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Mình không biết dòng báo lỗi đó có vấn đề gì không ?
khi download ctrinh vào chíp thì nó báo:
Programming Target...
ICDWarn0021: No Vdd voltage detected at Target. Continue with operation?
...Validating configuration fields
...Erasing Part
...Programming Program Memory (0x0 - 0x97)
Verifying...
ICDWarn0021: No Vdd voltage detected at Target. Continue with operation?
...Program Memory
...Verify Succeeded
Programming Configuration Bits
ICDWarn0021: No Vdd voltage detected at Target. Continue with operation?
.. Config Memory
Verifying configuration memory...
...Verify Succeeded
...Programming succeeded
18-Oct-2009, 11:22:39

MPLAB ICD 2 ready for next operation

--------------------------
Còn khi Upload ra thì nó báo:
Connecting to MPLAB ICD 2
...Connected
Setting Vdd source to target
Target Device PIC16F877A found, revision = Rev 0x8
...Reading ICD Product ID
Running ICD Self Test
... Failed Self Test. See ICD2 Settings (Programmer->Settings) (status tab) for details.
MPLAB ICD 2 ready for next operation
Reading...
ICDWarn0021: No Vdd voltage detected at Target. Continue with operation?
ICDWarn0038: When using auto-calculate write range, reads cover the entire memory range. Do you wish to continue?
...EEPROM
...Program Memory (0x0 - 0x1FFF)
.. Config Memory
...User ID Memory
...Read Succeeded
MPLAB ICD 2 ready for next operation

Ai biết chỉ mình với nhé.