MFM8516 - 70/90/12/15
ISSUE 4.7 : NOVEMBER 1998
Operating Modes
The following modes are used to control the device.
OPERATION
CS
L
OE
L
WE
H
A0
A0
X
A1
A1
X
A6
A6
X
A9
A9
X
I /O
DOUT
Read(1)
Standby
H
L
X
X
High Z
High Z
Din
Output Disable
H
H
L
H
X
X
X
X
Write
L
L
A0
L
A1
H
A6
L
A9
VID
VID
Verify Sector Protect
Auto-Select Device Unprotected Code
L
H
Code
Code
L
L
H
H
H
L
1) L=VIL, H=VIH, X=Don't Care
NOTE:
1) WE can be VIL if OE is VIL , OE at VIH initiates write operation.
D7 Data Polling
The MFM8516 features Data Polling as a method to indicate to the host system that the Embedded Algo-
rithms are in progress or completed. During the Embedded Programming Algorithm, an attempt to read the
device will produce complement data of the data last written to D7. Upon completion of the Embedded Pro-
gramming Algorithm an attempt to read the device will produce the true data last written to D7. During the
Embedded Erase Algorithm, During the Embedded Erase Algorithm, an attempt to read the device will pro-
duce a "0" at the D7 output.
For chip erase, the Data Polling is valid after the rising edge of the six WE pulse in the six write pulse se-
quence. For sector erase, the Data Polling is valid after the last rising edge of the sector erase WE pulse. Data
Polling must be performed at sector address within any of the sectors being erased or not a protected sector.
Otherwise, the status may not be valid. Once the Embedded Algorithm operation is close to being completed,
the device data pins (D7) may change asynchronously while OE is asserted low. This means that the device is
driving status information on D7 at one instant of time and then that byte's valid data at the next instant of time.
Depending on when the system samples the D7 output, it may read the status or valid data. Even if the device
has completed the Embedded Algorithm operation and D7 has a valid data, the data outputs on D0-D6 may
still be invalid. The valid data on D0-D7 will be read on the successive read attempts.
The Data Polling feature is only active during the Embedded Programming Algorithm, Embedded Erase
Algorithm, or sector erase time-out.
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MOSAIC [ MOSAIC ]
