ATtiny167-ESSZ datasheet(279/282 Pages) ATMEL

279 / 282 page

279

7728D–AVR–07/09

ATtiny87/ATtiny167

The time-out counter is disabled during the RESPONSE when this workaround is set.

Gain control of the crystal oscillator.

The crystal oscillator (0.4 -> 16 MHz) doesn’t latch its gain control (CKSEL/CSEL[2..0]

bits):

The ‘Recover System Clock Source’ command doesn’t returns CSEL[2..0] bits.

The gain control can be modified on the fly if CLKSELR changes.

Problem fix / workaround .

No workaround.

As soon as possible, after any CLKSELR modification, re-write the appropriate crystal

oscillator setting (CSEL[3]=1 and CSEL[2..0] / CSUT[1..0] bits) in CLKSELR.

Code example:

; Select crystal oscillator ( 16MHz crystal, fast rising power)

ldi

temp1,((0x0F<<CSEL0)|(0x02<<CSUT0))

sts

CLKSELR, temp1

; Enable clock source (crystal oscillator)

ldi

temp2,(1<<CLKCCE)

ldi

temp3,(0x02<<CLKC0)

; CSEL = "0010"

sts

CLKCSR,temp2

; Enable CLKCSR register access

sts

CLKCSR,temp3

; Enable crystal oscillator clock

; Clock source switch

ldi

temp3,(0x04<<CLKC0)

; CSEL = "0100"

sts

CLKCSR,temp2

; Enable CLKCSR register access

sts

CLKCSR,temp3

; Clock source switch

; Select watchdog clock ( 128KHz, fast rising power)

ldi

temp3,((0x03<<CSEL0)|(0x02<<CSUT0))

sts

CLKSELR, temp3

; (*)

; (*) !!! Loose gain control of crystal oscillator !!!

; ==> WORKAROUND ...

sts

CLKSELR, temp1

; ...

‘Disable Clock Source’ command remains enabled.

In the Dynamic Clock Switch module, the ‘Disable Clock Source’ command remains run-

ning after disabling the targeted clock source (the clock source is set in the CLKSELR

Problem fix / workaround.

After a ‘Disable Clock Source’ command, reset the CLKCSR register writing 0x80.

Code example:

; Select crystal oscillator

ldi

temp1,(0x0F<<CSEL0)

sts

CLKSELR, temp1

; Disable clock source (crystal oscillator)

ldi

temp2,(1<<CLKCCE)

ldi

temp3,(0x01<<CLKC0)

; CSEL = "0001"

sts

CLKCSR,temp2

; Enable CLKCSR register access

ATtiny167-ESSZ датащи(PDF) 279 Page - ATMEL Corporation

ATtiny167-ESSZ датащи(HTML) 279 Page - ATMEL Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL