Zoom Control; Eeprom - Canon 580EXII Service Manual

. Zoom Control

(1) The focal length information from the camera is input through the EFIDO terminal.
(2) If the focal length has changed, the focal length is displayed on the LCD panel and output
from either pin 5, 6 or 7 of IC107S and input to either pin 2, 3, or 4 of IC18.
(3) This input causes a change at pins 7-10 which causes the stepping motor to move the
flash head accordingly.
(4) This movement is based on the timing when pin 102 of IC107S detected the signal of
Photo-interrupter P301.
(5) The motor runs until the focal length information from the camera matches the stepping
motor position.
(6) Q35 is a voltage regulator and the output (constant 4V) is supplied to IC18. Q35 output
is constantly approx. 4V. It is input to pin 1 of IC18 and is supplied via an internal bridge
to pins 7-10 and input to the motor.
(7) The signal from IC107S pin 7 to IC18 pin 3 turns on IC18 establishing the reference
voltage.
* Flash coverage is set automatically. If bounce flash is set, flash coverage is set to 50mm
and the zoom display on the LCD will show --mm. During bounce flash, the focal length
information from the camera is ignored (flash coverage is fixed at 50mm).
Flash coverage can also be set manually. If it is set manually, the "M" icon and the set
focal length will be displayed on the LCD.
* When there is no signal of P301 for the initial position detection of the stepping motor,
a zoom error declared --mm is displayed and the stepping motor is stopped.
The stepping motor is referenced by the P301 signal when power is turned on and
zoom operated 20 times.
<Operation Sequence>
(1) → (2) → (3) → (4) → (5), (6), (7)

. EEPROM

(1) IC107S communicates with the EEPROM only in the following cases: After the power
turns on immediately after IC107S is reset, after the SE mode is canceled, and when data
is to be modified. The data in EEPROM is written and read.
(2) The clock line of IC107S pin 37 is used for the synchronization of the reading and
writing of EEPROM data.
(3) IC107S pin 35 and pin 36 line is used to read and write EEPROM data.
<Operation Sequence>
(1) → (2) (3)

Technical Information