AN977 Datasheet, PDF (3/17 Pages) STMicroelectronics – GUIDELINES FOR UPGRADING FROM THE ST92F120

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
(V_DD = 5 V ± 10%, T_A = –40° C to +125° C, unless otherwise specified)
Symbol
Parameter
V_IH
V_IL
V_HYS
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]
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]
Input Low Level
High Hyst.Schmitt Trigger
P4[7:6]-P6[5:4]
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]
Input Hysteresis
High Hyst. Schmitt Trigger
P4[7:6]
Input Hysteresis
High Hyst. Schmitt Trigger
P6[5:4]
Device
ST92F120
Min
0.7 x V_DD
Value
Typ⁽¹⁾
Max
Unit
V
ST92F124/F150/F250 0.6 x V_DD
V
ST92F120
0.8
V
ST92F124/F150/F250
ST92F120
ST92F124/F150/F250
ST92F120
0.2 x V_DD
V
0.3 x V_DD
V
0.25 x V_DD V
600
mV
ST92F124/F150/F250
250
mV
ST92F120
800
mV
ST92F124/F150/F250
1000
mV
ST92F120
900
mV
ST92F124/F150/F250
1000
mV
(1) _{Unless otherwise stated, typical data are based on TA= 25°C and VDD= 5V. They are only reported}
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
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