ISSUE 4.7 : NOVEMBER 1998
MFM8516 - 70/90/12/15
DEVICE OPERATION
Read Mode
The MFM8516 has two control functions which must be satisfied in order to obtain data at the outputs
CS is the power control and should be used for device selection.
OE is the output control and should be used to gate data to the output pins if the device is selected.
Standby Mode
Two standby modes are available : CMOS standby : CS held at Vcc +/- 0.5V
TTL standby :
CS held at VIH
In the standby mode the outputs are in a high impedance state independent of the OE input. If the device is
deselected during erasure or programming the device will draw active current until the operation is completed.
Output Disable
With the OE input at a logic high level (VIH), output from the device is disabled. This will cause the output pins
to be in a high impedance state.
Autoselect
This mode is intended for use by programming equipment. This mode is functional over the full military
temperature range. The autoselect codes as follows :
Type
A18
A17
A16
A6
A1
A0
Code
(HEX)
D7
D6
D5
D4
D3
D2
D1
D0
Sector
Protection
Sector Address
VIL
VIH
VIL
01H*
0
0
0
0
0
0
0
1
* Outputs 01H at protected sector address
To activate this mode the programming equipment must force VID on address A9 . All addresses are don't
care apart from A0, A1 & A6.
Write
Device erasure and programming are accomplished via the command register. The contents of the register
serve as inputs to the internal state machine. The state machine outputs dictate the function of the device.
The register is a latch used to store the commands along with the address and data information required to
execute the command. The command register is written by bringing WE to VIL while CS is at VIL and
OE is at VIH. Addresses are latched on the falling edge of WE or CS, whichever happens later; while data is
latched on the rising edge of WE or CS, whichever happens first.
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MOSAIC [ MOSAIC ]
