diff --git a/okean240/constants.go b/okean240/constants.go
index 84c6ccb..bff05c7 100644
--- a/okean240/constants.go
+++ b/okean240/constants.go
@@ -104,10 +104,10 @@ const RstTimerNo = 4
 //const Rst7Mask = 0x80 // User device 1 interrupt
 
 // PicDd75a Port A (a0=0)
-//const PicDd75a = 0x80
+const PicDd75a = 0x80
 
 // PIC_DD75B Port B (a0=1)
-//const PIC_DD75B = 0x81
+const PicDd75b = 0x81
 
 /*
  * КР580ВВ51 DD72
@@ -143,8 +143,8 @@ const SysDd17ctr = 0xC3
 // LPT_DD67PA Port A - Printer Data
 //const LPT_DD67PA = 0xE0
 
-// VID_DD67PB Port B - Video control [VSU,C/M,FL3:1,COL3:1]
-//const VID_DD67PB = 0xE1
+// VidDd67pb Port B - Video control [VSU,C/M,FL3:1,COL3:1]
+const VidDd67pb = 0xE1
 
 // DD67PC Port C - [USER3:1, STB-LP, BELL, TAPE3:1]
 //const DD67PC = 0xE2
diff --git a/okean240/ioports.go b/okean240/ioports.go
index 14bcc10..21924a3 100644
--- a/okean240/ioports.go
+++ b/okean240/ioports.go
@@ -15,6 +15,8 @@ func (c *ComputerType) IORead(port uint16) byte {
 	case PicDd75a:
 		// PIO xx59, get IRR register
 		return c.pic.IRR()
+	case PicDd75b:
+		return c.pic.CSW()
 	case UartDd72rr:
 		// USART VV51 CMD
 		return c.usart.Status()
@@ -56,7 +58,7 @@ func (c *ComputerType) IOWrite(port uint16, val byte) {
 		}
 	case SysDd17ctr:
 		c.dd17EnableOut = val == 0x80
-	case VID_DD67PB:
+	case VidDd67pb:
 		if val&VidVsuBit == 0 {
 			// video page 0
 			c.vRAM = c.memory.allMemory[VRAMBlock0]
@@ -96,6 +98,8 @@ func (c *ComputerType) IOWrite(port uint16, val byte) {
 	case UartDd72rd:
 		// USART VV51 Data
 		c.usart.Send(val)
+	case PicDd75b:
+		c.pic.SetCSW(val)
 	case FdcCmd:
 		c.fdc.SetCmd(val)
 	case FdcData:
diff --git a/okean240/pic/pic8259.go b/okean240/pic/pic8259.go
index 67e7a01..22c399c 100644
--- a/okean240/pic/pic8259.go
+++ b/okean240/pic/pic8259.go
@@ -11,11 +11,14 @@ import log "github.com/sirupsen/logrus"
 
 type I8259 struct {
 	irr byte
+	csw byte
 }
 
 type I8259Interface interface {
 	SetIRQ(irq byte)
 	IRR() byte
+	CSW() byte
+	SetCSW(val byte)
 }
 
 func (c *I8259) IRR() byte {
@@ -47,6 +50,14 @@ func (c *I8259) SetIRQ(irq byte) {
 	}
 }
 
+func (c *I8259) CSW() byte {
+	return c.csw
+}
+
+func (c *I8259) SetCSW(val byte) {
+	c.csw = val
+}
+
 func New() *I8259 {
 	return &I8259{
 		irr: 0,