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GUIDELINES FOR UPGRADING FROM THE ST92F120 (0.50 µm) TO THE ST92F124...

1.3 SCHMITT TRIGGERS

– I/O ports with Special Schmitt Triggers are no longer present on the ST92F124/F150/F250

but are replaced by I/O ports with High Hysteresis Schmitt Triggers. The related I/O pins are:

P6[5-4].

– Differences on the VIL and VIH. See Table 2.

Table 2. Input Level Schmitt Trigger DC Electrical Characteristics

(1)

for design guide lines not tested in production.

1.4 MEMORY ORGANIZATION

1.4.1 External memory

On the ST92F120, only 16 bits were externally available. Now, on the ST92F124/F150/F250

device, the 22 bits of the MMU are externally available. This organization is used to make it

Symbol

Parameter

Device

Value

Unit

Min

Max

Input High Level

Standard Schmitt Trigger

P2[5:4]-P2[1:0]-P3[7:4]-P3[2:0]-

P4[4:3]-P4[1:0]-P5[7:4]-P5[2:0]-

P6[3:0]-P6[7:6]-P7[7:0]-P8[7:0]-

P9[7:0]

ST92F120

V

ST92F124/F150/F250

V

Input Low Level

Standard Schmitt Trigger

P2[5:4]-P2[1:0]-P3[7:4] P3[2:0]-

P4[4:3]-P4[1:0]-P5[7:4]-P5[2:0]-

P6[3:0]-P6[7:6]-P7[7:0]-P8[7:0]-

P9[7:0]

ST92F120

0.8

V

ST92F124/F150/F250

V

Input Low Level

High Hyst.Schmitt Trigger

P4[7:6]-P6[5:4]

ST92F120

V

ST92F124/F150/F250

V

Input Hysteresis

Standard Schmitt Trigger

P2[5:4]-P2[1:0]-P3[7:4]-P3[2:0]-

P4[4:3]-P4[1:0]-P5[7:4]-P5[2:0]-

P6[3:0]-P6[7:6]-P7[7:0]-P8[7:0]-

P9[7:0]

ST92F120

600

mV

ST92F124/F150/F250

250

mV

Input Hysteresis

High Hyst. Schmitt Trigger

P4[7:6]

ST92F120

800

mV

ST92F124/F150/F250

1000

mV

Input Hysteresis

High Hyst. Schmitt Trigger

P6[5:4]

ST92F120

900

mV

ST92F124/F150/F250

1000

mV