MOVX A, @ DPTR     Move external RAM (16-bit address) to

ACC

MOVX @ DPTR , A    Move ACC to external RAM (16-bit

address)

JMP @ A + DPTR     Jump indirect relative to DPTR

The data pointer can be accessed on a byte-by-byte basis by specifying the low or high byte in an instruction which accesses the SFRs. See application note AN458 for more details.

NOTES:

1. Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any conditions other than those described in the AC and DC Electrical Characteristics section of this specification is not implied.

2. This product includes circuitry specifically designed for the protection of its internal devices from the damaging effects of excessive static charge. Nonetheless, it is suggested that conventional precautions be taken to avoid applying greater than the rated maximum.

3. Parameters are valid over operating temperature range unless otherwise specified. All voltages are with respect to VSS unless otherwise noted.

 DC ELECTRICAL CHARACTERISTICS

Tamb = 0°C to +70°C or –40°C to +85°C; 5 V ±10%; VSS = 0 V

 NOTES:

1.Typical ratings are not guaranteed. The values listed are at room temperature, 5 V.

2. Capacitive loading on ports 0 and 2 may cause spurious noise to be superimposed on the VOLs of ALE and ports 1 and 3. The noise is due to external bus capacitance discharging into the port 0 and port 2 pins when these pins make 1-to-0 transitions during bus operations. In the

worst cases (capacitive loading > 100pF), the noise pulse on the ALE pin may exceed 0.8V. In such cases, it may be desirable to qualify ALE with a Schmitt Trigger, or use an address latch with a Schmitt Trigger STROBE input. IOL can exceed these conditions provided that no single output sinks more than 5 mA and no more than two outputs exceed the test conditions.

3. Capacitive loading on ports 0 and 2 may cause the VOH on ALE and PSEN to momentarily fall below the VCC–0.7 specification when the address bits are stabilizing.

4. Pins of ports 1, 2 and 3 source a transition current when they are being externally driven from 1 to 0. The transition current reaches its maximum value when VIN is approximately 2 V.

5. See Figures 22 through 25 for ICC test conditions and Figure 21 for ICC vs Freq.  Active mode: ICC(MAX) = (0.9 × FREQ. + 20)mA Idle mode: ICC(MAX) = (0.37 × FREQ. +1.0)mA

6. This value applies to Tamb = 0°C to +70°C.

7. Load capacitance for port 0, ALE, and PSEN = 100pF, load capacitance for all other outputs = 80 pF.

8. Under steady state (non-transient) conditions, IOL must be externally limited as follows:

Maximum IOL per port pin: 15 mA (*NOTE: This is 85°C specification.)

Maximum IOL per 8-bit port: 26 mA

Maximum total IOL for all outputs: 71 mA

If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater than the listed

test conditions.

9. ALE is tested to VOH1, except when ALE is off then VOH is the voltage specification.

10.Pin capacitance is characterized but not tested. Pin capacitance is less than 25 pF.  Pin capacitance of ceramic package is less than 15 pF

(except EA is 25 pF).

 AC ELECTRICAL CHARACTERISTICS

Tamb = 0°C to +70°C or –40°C to +85°C, VCC = 5 V ±10%, VSS = 0V1,

NOTES:

1. Parameters are valid over operating temperature range unless otherwise specified.

2. Load capacitance for port 0, ALE, and PSEN = 100 pF, load capacitance for all other outputs = 80 pF.

3. Interfacing the microcontroller to devices with float times up to 45 ns is permitted. This limited bus contention will not cause damage to Port 0 drivers. 闪存微控制器英文文献和中文翻译(3):http://www.751com.cn/fanyi/lunwen_49448.html