Motor de Búsqueda de Datasheet de Componentes Electrónicos
Selected language     Spanish  ▼

Delete All
ON OFF
ALLDATASHEET.ES

X  

Preview PDF Download HTML

MC908QL2V Datasheet(PDF) 91 Page - Motorola, Inc

No. de Pieza. MC908QL2V
Descripción  Microcontrollers
Descarga  222 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Fabricante  MOTOROLA [Motorola, Inc]
Página de inicio  http://www.freescale.com
Logo 

MC908QL2V Datasheet(HTML) 91 Page - Motorola, Inc

Zoom Inzoom in Zoom Outzoom out
 91 / 222 page
background image
Functional Description
MC68HC908QL4 • MC68HC908QL3 • MC68HC908QL2 Data Sheet, Rev. 4
Freescale Semiconductor
91
The keyboard interrupt latch is set when one or more enabled keyboard interrupt inputs are asserted.
If the keyboard interrupt sensitivity is edge-only, for KBIPx = 0, a falling (for KBIPx = 1, a rising)
edge on a keyboard interrupt input does not latch an interrupt request if another enabled keyboard
pin is already asserted. To prevent losing an interrupt request on one input because another input
remains asserted, software can disable the latter input while it is asserted.
If the keyboard interrupt is edge and level sensitive, an interrupt request is present as long as any
enabled keyboard interrupt input is asserted.
Figure 9-2. Keyboard Interrupt Block Diagram
9.3.1.1 MODEK = 1
If the MODEK bit is set, the keyboard interrupt inputs are both edge and level sensitive. The KBIPx bit will
determine whether a edge sensitive pin detects rising or falling edges and on level sensitive pins whether
the pin detects low or high levels. With MODEK set, both of the following actions must occur to clear a
keyboard interrupt request:
Return of all enabled keyboard interrupt inputs to a deasserted level. As long as any enabled
keyboard interrupt pin is asserted, the keyboard interrupt remains active.
Vector fetch or software clear. A KBI vector fetch generates an interrupt acknowledge signal to
clear the KBI latch. Software generates the interrupt acknowledge signal by writing a 1 to ACKK in
KBSCR. The ACKK bit is useful in applications that poll the keyboard interrupt inputs and require
software to clear the KBI latch. Writing to ACKK prior to leaving an interrupt service routine can
also prevent spurious interrupts due to noise. Setting ACKK does not affect subsequent transitions
KBI LATCH
KEYBOARD
INTERRUPT
REQUEST
ACKK
INTERNAL BUS
RESET
KBIE0
KBI0
0
1
S
KBIP0
KBIEx
KBIx
0
1
S
KBIPx
DQ
CK
CLR
VDD
MODEK
IMASKK
SYNCHRONIZER
KEYF
TO PULLUP/
TO PULLUP/
PULLDOWN ENABLE
PULLDOWN ENABLE
VECTOR FETCH
DECODER
AWUIREQ
(SEE Figure 4-1)
NOTE:
To enable internal pullup/pulldown, requires both the KBIPx and the corresponding PTAPUEN to both be set.
(see Note)
(see Note)


Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54  55  56  57  58  59  60  61  62  63  64  65  66  67  68  69  70  71  72  73  74  75  76  77  78  79  80  81  82  83  84  85  86  87  88  89  90  91  92  93  94  95  96  97  98  99  100   ...More


Datasheet Download




Enlace URL




Privacy Policy
ALLDATASHEET.ES
Does ALLDATASHEET help your business so far?  [ DONATE ]  

Todo acerca de Alldatasheet   |   Publicidad   |   Contáctenos   |   Política de Privacidad   |   Favorito   |   Intercambio de Enlaces   |   Lista de Fabricantes
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn