Editing nec/μcom-42/μpd555

{{nec title|μPD555 (μCOM-42 EVACHIP)}}
{{mcu
| image           = <!-- foobar.png                -->
| caption         = <!-- description of foobar.png -->
| name            = NEC μCOM-42 EVACHIP
| manufacturer    = NEC
| model number    = μCOM-42 EVACHIP
| part number     = μPD555
| first launched  = 1977
| family          = μCOM-42
| clock min       = 100 kHz
| clock max       = 200 kHz
| microarch       = μCOM-42
| process         = 
| tech            = pMOS
| word size       = 4 bit
| electrical      = yes
| temp max        = 70 °C
| temp min        = -10 °C
| vdd             = -10 V
| vss             = 0 V
| memory          = yes
| rom             = 
| rom break       = 
| ram             = 48 B
| ram break       = 96x4 bit
| max memory addr = 2.4 kB
| stack levels    = 4
| pins            = yes
| pin count       = 64
| irq lines       = 2
| io lines        = 1
| i lines         = 1
| o lines         = 12
| packaging       = yes
| package         = DIP64
| package type    = DIP
| package 1       = CerDIP64
| package type 1  = CerDIP
}}
The '''μPD555''' or '''μCOM-42 EVACHIP''' is a {{arch|4}} evaluation/developerment [[microcontroller]] used for both software and hardware debugging of the {{nec|μPD548}} microcontroller.

The 555 is functionally identical to the {{nec|μPD548}} without the internal memory, which instead is needed to be supplied externally and connected via the additional pins. This chip also has a HOLD operation that allows step-by-step inspection of operations.

== Design ==
{{empty section}}

== Instruction Set ==
{{main|/μcom-42 isa|l1=μCOM-42 ISA}}
{{empty section}}

== Documents ==
* [[:File:NEC μPD555.pdf|NEC μPD555 datasheet]]

== See also ==
* {{nec|μCOM-42}}
* {{nec|μCOM-4}}
* {{nec|μCOM-8}}
family	μCOM-42 +
first launched	1977 +
full page name	nec/μcom-42/μpd555 +
instance of	microcontroller +
manufacturer	NEC +
max operating temperature	70 °C +
microarchitecture	μCOM-42 +
min operating temperature	-10 °C +
model number	μCOM-42 EVACHIP +
name	NEC μCOM-42 EVACHIP +
package	DIP64 + and CerDIP64 +
part number	μPD555 +
pin count	64 +
ram	4.8e-5 MB (0.048 kB, 48 B, 384 b, 4.8e-8 GB) +
ram breakdown	96x4 bit +
technology	pMOS +
word size	4 bit (0.5 octets, 1 nibbles) +