I need to run C8051F500 with external
crystal 24M.
Unfortunatelly, Config2 recommented code,
nor another recommendations from SiLabs forums are not working. There is no oscillation. XTAL1,2 == 0.
Have tryed number of crystals, capacitors etc.

Chip environment:
- Vregin = 5v
- internal Vregulator = 2.6v (default)
- Vdd wired to Vdda (with capacitors)
- Gnd wired to Gnda
- crystal = 24M
- crystal capacitors = 22pF (10pF-same result)
- crystal load = 10MOhm (1M-same result)
- watch dog - disabled

Code (on Startup):
mov SFRPAGE, #0Fh
mov OSCICN, #11010111b
mov P0MDIN, #11110011b
mov P0SKIP, #00001100b
mov XBR2, #040h
orl P0, #0Ch
mov OSCXCN, #67h

call Delay_1mS
mov r1, #200

osc_wait: ; wait for XTLVLD-->1 (osc ready)
mov a, OSCXCN
jb Acc.7, OSC_OK
call Delay_1mS
djnz r1, osc_wait
; ---- osc not working
OSC_OK:
; osc ok
--------------
OSCXCN.7 never gets '1'

All above conforms to F500 datasheet.
What is wrong?
Could you help me?

I have read the section 19 of F500
datasheet carefully.

Registers settings are:
(from start of this topic)
mov SFRPAGE, #0Fh
mov OSCICN, #11010111b
mov P0MDIN, #11110011b
mov P0SKIP, #00001100b
mov XBR2, #040h
orl P0, #0Ch
mov OSCXCN, #67h
.....

Is something wrong or forgotten?

Delay_1ms does 1ms delay with 24M oscillator. With /128 prescaller
it will do 128ms delay. I think, this is
not important.

There is one strange fragment form F50x (and F58x) datasheet (19.4.1):
"The recommended procedure is:
1. Force XTAL1 and XTAL2 to a high state.
This involves enabling the Crossbar
and writing 1 to the port pins associated
with XTAL1 and XTAL2."

F500_Oscillator_Crystal.c does not set
XTAL1,2 pins explisity.

F500_Oscillator_Crystal.c does not set
XTAL1,2 pins explisity.

if you look at the SFR descriptions in the datasheet you will in the header see "reset state" have a look

Erik

May be, my F500 chip is defective.
Will try with another F500 chip, as soon
as finish the preliminary hw/sw debug.

Thus you will SAVE lots of money by buying a devboard. That will give you definite answer re custom hardware functioning or not

Regards,