89C5121-SK1 Atmel, 89C5121-SK1 Datasheet - Page 18

• Manufacturer Part Number: 89C5121-SK1
• Description: KIT SMART CARD FOR AT89C5121
• Manufacturer: Atmel
• Type: Smart Cardr

Specifications of 89C5121-SK1

• Contents: Board
• For Use With/related Products: AT89C5121
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: T89C5121-SK1; T89C5121-SK1

Reduced EMI Mode
Power Modes Control
Registers
18
A/T8xC5121
The ALE signal is used to demultiplex address and data buses on port 0 when used with
external program or data memory. Nevertheless, during internal code execution, ALE
signal is still generated.
Only in case of PLCC52 version, in order to reduce EMI, ALE signal can be disabled by
setting AO bit.
The AO bit is located in AUXR register at bit location 0 (See Table 4). As soon as AO is
set, ALE is no longer output but remains active during MOVX and MOVC instructions
and external fetches. During ALE disabling, ALE pin is weakly pulled high.
Table 3. PCON Register
PCON (S:87h)
Power Configuration Register
Reset Value = X0XX XX00b
Number
SMOD1
Bit
7
6
5
4
3
2
1
0
7
Mnemonic Description
SMOD1
SMOD0
LEDPD
SMOD0
GF0
Bit
PD
IDL
6
Double Baud Rate bit
Set to double the Baud Rate when Timer 1 is used and mode 1, 2 or 3 is selected in
SCON register.
SCON Select bit
When cleared, read/write accesses to SCON.7 are to SM0 bit and read/write
accesses to SCON.6 are to SM1 bit.
When set, read/write accesses to SCON.7 are to FE bit and read/write accesses to
SCON.6 are to OVR bit. SCON is Serial Port Control register.
Reserved
Reserved
LED Control Power-Down Mode bits
When cleaned the I/O pull-up is the standard C51 pull-up control. When set the
medium pull-up is disconnected.
General-purpose flag 0
One use is to indicate wether an interrupt occurred during normal operation or
during Idle mode.
Power-down Mode bit
Cleared by hardware when an interrupt or reset occurs.
Set to activate the Power-down mode.
If IDL and PD are both set, PD takes precedence.
Idle Mode bit
Cleared by hardware when an interrupt or reset occurs.
Set to activate the Idle mode.
If IDL and PD are both set, PD takes precedence.
5
-
4
-
LEDPD
3
GF0
2
PD
1
4164G–SCR–07/06
IDL
0